ORCID Profile
0000-0001-7484-3738
Current Organisations
University of New South Wales
,
University of Cambridge
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Condensed Matter Physics—Electronic And Magnetic Properties; | Electronic and Magnetic Properties of Condensed Matter; Superconductivity | Condensed Matter Physics | Nanotechnology | Mathematical Physics | Nanotechnology | Theoretical Physics | Functional Materials | Quantum Information, Computation and Communication | Nanoelectronics | Optics And Opto-Electronic Physics | Condensed Matter Modelling and Density Functional Theory | Electronic and magnetic properties of condensed matter; superconductivity | Materials Engineering | Condensed Matter Physics—Structural Properties | Electrical and Electronic Engineering | Nanoscale Characterisation | Nanomaterials | Materials Engineering Not Elsewhere Classified | Condensed Matter Characterisation Technique Development | Quantum information computation and communication | Condensed matter physics | Physical Organic Chemistry | Colloid And Surface Chemistry | Microelectronics and Integrated Circuits | Photodetectors, Optical Sensors and Solar Cells | Chemical Sciences Not Elsewhere Classified | Quantum physics | Functional materials | Condensed matter characterisation technique development | Other Electronic Engineering | Compound Semiconductors | Organic Chemistry Not Elsewhere Classified | Organic Semiconductors | Composite and Hybrid Materials | Quantum Optics And Lasers | Organic Chemistry | Biomaterials | Macromolecular and Materials Chemistry | Biotechnology Not Elsewhere Classified | Proteins and Peptides | Nanotechnology not elsewhere classified | Nanophotonics | Interdisciplinary Engineering Not Elsewhere Classified | Surfaces and Structural Properties of Condensed Matter | Degenerate Quantum Gases and Atom Optics | Nanofabrication, Growth and Self Assembly
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Physical Sciences | Integrated circuits and devices | Physical sciences | Expanding Knowledge in Technology | Integrated Circuits and Devices | Expanding Knowledge in Engineering | Chemical sciences | Other | Information processing services | Energy Storage (excl. Hydrogen) | Computer hardware and electronic equipment not elsewhere classified | Management of Greenhouse Gas Emissions from Information and Communication Services | Scientific instrumentation | Solar-Thermal Electric Energy | Communication services not elsewhere classified | Commercial Energy Conservation and Efficiency | Solar-Photovoltaic Energy | Polymeric materials (e.g. paints) | Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Biological Sciences | Communication equipment not elsewhere classified |
Related Links
Publications
Crystallographic anisotropy of the Zeeman splitting in 1D hole quantum wires
Publisher: Elsevier BV
Date: 02-2010
An improved process for fabricating high-mobility organic molecular crystal field-effect transistors
Publisher: AIP Publishing
Date: 15-10-2007
DOI: 10.1063/1.2802284
Abstract: In this paper we present an improved process for producing elastomer transistor st s and high-mobility organic field-effect transistors (FETs) based on semiconducting acene molecular crystals. In particular, we have removed the need to use a silanized Si wafer for curing the st s and to handle a fragile micron thickness polydimethylsiloxane (PDMS) insulating film and laminate it, bubble-free, against the PDMS transistor st . We find that despite the altered design, rougher PDMS surface, and lamination and measurement of the device in air, we still achieve electrical mobilities of the order of 10cm2∕Vs, comparable to the current state of the art in organic FETs. Our device shows hole conduction with a threshold voltage of the order of −9V, which corresponds to a trap density of 1.4×1010cm−2.
Encapsulation of phosphorus dopants in silicon for the fabrication of a quantum computer
Publisher: AIP Publishing
Date: 21-10-2002
DOI: 10.1063/1.1516859
G-factor and well width variations for the two-dimensional hole gas in surface conducting diamond
Publisher: AIP Publishing
Date: 22-01-2018
DOI: 10.1063/1.5010800
Abstract: Hydrogen-terminated diamond possesses a quasi two-dimensional, sub-surface hole accumulation layer with a strong and tunable spin-orbit coupling due to surface transfer doping. We report a magnetoresistance study of the phase coherent backscattering (weak localization and antilocalization) at low temperatures. The response to an external magnetic field is highly anisotropic, confirming the 2D nature of the carriers despite the short mean free path. By simultaneously applying perpendicular and parallel magnetic fields, we are able to probe the Zeeman interaction and microroughness of the quantum well at the diamond surface. From a quantitative analysis of magnetoresistance curves at 2.5 K, we derive a hole g-factor of 2.6±0.1 and rms fluctuations in the width of the hole quantum well of about 3 nm over the phase coherence length of 33 nm. Well width fluctuations are ascribed to surface roughness and to lateral fluctuations in carrier density, which self-consistently determines the width of the confining potential.
Erratum: Manifestation of a non-Abelian Berry phase in a p -type semiconductor system (Physical Review B - Condensed Matter and Materials Physics (2016) 93 (205424) DOI: 10.1103/PhysRevB.93.205424)
Publisher: American Physical Society (APS)
Date: 13-06-2016
Electrical control of the
g
Publisher: American Physical Society (APS)
Date: 17-12-2021
TUNNELING AND HOPPING BETWEEN DOMAINS IN THE METAL-INSULATOR TRANSITION IN TWO-DIMENSIONS
Publisher: World Scientific Pub Co Pte Lt
Date: 20-10-2008
DOI: 10.1142/S0217979208050310
Abstract: Motivated by recent surprising experimental results for temperature dependent resistivities in 2D mesoscopic electron systems, we investigate transport in these systems by percolation connected through a network of metallic domains. The size of the domains is determined by the level of disorder in the system and by the strength of the electron correlations. In the insulating phase the metallic domains are connected for transport by two competing mechanisms, thermally activated hopping and quantum tunneling. We calculate the transmission across the potential barriers that separate the metallic domains. Using recent data from transport measurements in mesoscopic 2D systems, we obtain the observed saturation of the temperature dependent resistivity at T ~ 1 K and consistent values for the size of the domains and for magnitude of the average variation in the random disorder potential.
Modeling of electrostatic gate operations in the Kane solid state quantum computer
Publisher: SPIE
Date: 21-11-2001
DOI: 10.1117/12.449136
Anomalous integer quantum Hall states in coupled double quantum wells and the effect of Landau level broadening
Publisher: IOP Publishing
Date: 1999
Improving reproducibility of quantum devices with completely undoped architectures
Publisher: AIP Publishing
Date: 02-11-2020
DOI: 10.1063/5.0024923
Abstract: The reproducible operation of quantum electronic devices is a key requirement for future quantum information processing and spintronics applications. Traditionally, quantum devices have been fabricated from modulation-doped heterostructures, where there is an intrinsic lack of reproducibility due to the random potential from ionized donors. Here, we show that we can greatly improve reproducibility over modulation-doped devices by using a completely undoped architecture, with superior uniformity in the confinement potential and more consistent operating voltages for both electron and hole devices. Our results demonstrate that undoped heterostructures have significant advantages over modulation doping for reproducible manufacturing of quantum devices.
Enhanced Zeeman splitting in Ga0.25 In0.75 As quantum point contacts
Publisher: AIP Publishing
Date: 07-07-2008
DOI: 10.1063/1.2957033
Abstract: The strength of the Zeeman splitting induced by an applied magnetic field is an important factor for the realization of spin-resolved transport in mesoscopic devices. We measure the Zeeman splitting for a quantum point contact etched into a Ga0.25In0.75As quantum well, with the field oriented parallel to the transport direction. We observe an enhancement of the Landé g-factor from |g∗|=3.8±0.2 for the third subband to |g∗|=5.8±0.6 for the first subband, six times larger than in GaAs. We report subband spacings in excess of 10 meV, which facilitates quantum transport at higher temperatures.
Ground-plane screening of Coulomb interactions in two-dimensional systems: How effectively can one two-dimensional system screen interactions in another
Publisher: American Physical Society (APS)
Date: 05-10-2009
Spin blockade in hole quantum dots: Tuning exchange electrically and probing Zeeman interactions
Publisher: American Physical Society (APS)
Date: 26-05-2017
Hybrid architecture for shallow accumulation mode AlGaAs/GaAs heterostructures with epitaxial gates
Publisher: AIP Publishing
Date: 05-01-2015
DOI: 10.1063/1.4905210
Abstract: Accumulation mode devices with epitaxially grown gates have excellent electrical stability due to the absence of dopant impurities and surface states. We overcome typical fabrication issues associated with epitaxially gated structures (e.g., gate leakage and high contact resistance) by using separate gates to control the electron densities in the Ohmic and Hall bar regions. This hybrid gate architecture opens up a way to make ultrastable nanoscale devices where the separation between the surface gates and the 2D electron gas is small. In this work, we demonstrate that the hybrid devices made from the same wafer have reproducible electrical characteristics, with identical mobility and density traces over a large range of 2D densities. In addition, thermal cycling does not influence the measured electrical characteristics. As a demonstration of concept, we have fabricated a hybrid single-electron transistor on a shallow (50 nm) AlGaAs/GaAs heterostructure that shows clear Coulomb blockade oscillations in the low temperature conductance.
Landau level spin diode in a GaAs two dimensional hole system
Publisher: IOP Publishing
Date: 20-03-2015
Spin and orbital structure of the first six holes in a silicon metal-oxide-semiconductor quantum dot
Publisher: Springer Science and Business Media LLC
Date: 14-08-2018
DOI: 10.1038/S41467-018-05700-9
Abstract: Valence band holes confined in silicon quantum dots are attracting significant attention for use as spin qubits. However, experimental studies of single-hole spins have been hindered by challenges in fabrication and stability of devices capable of confining a single hole. To fully utilize hole spins as qubits, it is crucial to have a detailed understanding of the spin and orbital states. Here we show a planar silicon metal-oxide-semiconductor-based quantum dot device and demonstrate operation down to the last hole. Magneto-spectroscopy studies show magic number shell filling consistent with the Fock–Darwin states of a circular two-dimensional quantum dot, with the spin filling sequence of the first six holes consistent with Hund’s rule. Next, we use pulse-bias spectroscopy to determine that the orbital spectrum is heavily influenced by the strong hole–hole interactions. These results provide a path towards scalable silicon hole-spin qubits.
The effect of temperature and gas flow on the physical vapour growth of mm-scale rubrene crystals for organic FETs
Publisher: SPIE
Date: 21-12-2008
DOI: 10.1117/12.759015
Scaling of the Kondo zero-bias peak in a hole quantum dot at finite temperatures
Publisher: American Physical Society (APS)
Date: 14-05-2013
Observation of orientation- andk-dependent Zeeman spin-splitting in hole quantum wires on (100)-oriented AlGaAs/GaAs heterostructures
Publisher: IOP Publishing
Date: 24-03-2010
Erratum: Anomalous transport in mesoscopic inhomogeneous two-dimensional electron systems at low temperature [Phys. Rev. B82, 035310 (2010)]
Publisher: American Physical Society (APS)
Date: 06-09-2011
Ballistic transport in induced one-dimensional hole systems
Publisher: AIP Publishing
Date: 28-08-2006
DOI: 10.1063/1.2337525
Abstract: The authors have fabricated and studied a ballistic one-dimensional p-type quantum wire using an undoped AlGaAs∕GaAs heterostructure. The absence of modulation doping eliminates remote ionized impurity scattering and allows high mobilities to be achieved over a wide range of hole densities and, in particular, at very low densities where carrier-carrier interactions are strongest. The device exhibits clear quantized conductance plateaus with highly stable gate characteristics. These devices provide opportunities for studying spin-orbit coupling and interaction effects in mesoscopic hole systems in the strong interaction regime where rs& .
Spin-orbit interactions in inversion-asymmetric two-dimensional hole systems: A variational analysis
Publisher: American Physical Society (APS)
Date: 10-02-2017
Measuring the Charge and Spin States of Electrons on Individual Dopant Atoms in Silicon
Publisher: Springer Berlin Heidelberg
Date: 2009
Resistively Detected Nuclear Magnetic Resonance in n- and p-Type GaAs Quantum Point Contacts
Publisher: American Chemical Society (ACS)
Date: 13-07-2011
DOI: 10.1021/NL201211D
Abstract: We present resistively detected NMR measurements in induced and modulation-doped electron quantum point contacts, as well as induced hole quantum point contacts. While the magnitude of the resistance change and associated NMR peaks in n-type devices is in line with other recent measurements using this technique, the effect in p-type devices is too small to measure. This suggests that the hyperfine coupling between holes and nuclei in this type of device is much smaller than the electron hyperfine coupling, which could have implications in quantum information processing.
Back-gated split-gate transistor: A one-dimensional ballistic channel with variable Fermi energy
Publisher: AIP Publishing
Date: 06-1992
DOI: 10.1063/1.106849
Abstract: We have studied the quantized conductance of a one-dimensional ballistic channel in the two-dimensional electron gas of a back-gated GaAs/AlGaAs heterostructure. A standard Schottky split-gate fabricated with electron-beam lithography techniques is used to define the one-dimensional channel, but we incorporate an epitaxially grown in situ back-gate, situated ∼1 μm below the electron gas, to provide additional control of the carrier density. Quantized conductance steps can be induced by changing the bias on either gate, highlighting the self-consistent nature of the electrostatics involved. We show that we can, in principle, achieve independent control of the one-dimensional carrier density and channel width.
High electron mobility and low noise quantum point contacts in an ultra-shallow all-epitaxial metal gate GaAs/AlxGa1−xAs heterostructure
Publisher: AIP Publishing
Date: 09-08-2021
DOI: 10.1063/5.0053816
Abstract: The mobility of the two-dimensional electron gas (2DEG) in shallow GaAs/AlxGa1−xAs heterostructures is strongly suppressed by unwanted Coulomb scattering from surface charge, likely located in native surface oxides that form after the wafer is removed from the crystal growth system. Here, we show that this native surface oxide can be eliminated by growing an epitaxial aluminum gate before removing the wafer from the growth chamber. We fabricate accumulation mode devices on two wafers with nearly identical structures and growth conditions: one with an epitaxial aluminum gate 35 nm above the channel and another with an ex situ metal gate deposited on an aluminum oxide dielectric. Low temperature transport measurements show that the epitaxial gate design greatly reduces surface charge scattering, with up to 2.5× increase in mobility. Despite the ultra-shallow 2DEG (35 nm), the mobility remains high even at low carrier densities. Finally, we show that the epitaxial aluminum gate can be patterned to make nanostructures by fabricating a quantum point contact that shows robust and reproducible 1D conductance quantization, with extremely low charge noise.
Ground-plane screening of Coulomb interactions by a nearby two-dimensional system
Publisher: Elsevier BV
Date: 02-2010
Charge shelving and bias spectroscopy for the readout of a charge qubit on the basis of superposition states
Publisher: American Physical Society (APS)
Date: 07-2004
Transition from one- to two-subband occupancy in the 2DEG of back-gated modulation-doped GaAs-
Publisher:
American Physical Society (APS)
Date:
15-06-1995
Publisher: American Physical Society (APS)
Date: 15-06-1995
Ballistic transport in one-dimensional bilayer hole systems
Publisher: Elsevier BV
Date: 08-2006
TUNNELING AND HOPPING BETWEEN DOMAINS IN THE METAL-INSULATOR TRANSITION IN TWO-DIMENSIONS
Publisher: WORLD SCIENTIFIC
Date: 12-2008
Can insulating the gates lead us to stable modulation-doped hole quantum devices?
Publisher: IEEE
Date: 12-2010
Thickness-dependent electronic structure in WTe2 thin films
Publisher: American Physical Society (APS)
Date: 13-07-2018
Interaction correction to the longitudinal conductivity and Hall resistivity in high-quality two-dimensional GaAs electron and hole systems
Publisher: American Physical Society (APS)
Date: 21-12-2005
Ultra-shallow quantum dots in an undoped GaAs/AlGaAs two-dimensional electron gas
Publisher: AIP Publishing
Date: 11-03-2013
DOI: 10.1063/1.4795613
Abstract: We report quantum dots fabricated on very shallow 2-dimensional electron gases, only 30 nm below the surface, in undoped GaAs/AlGaAs heterostructures grown by molecular beam epitaxy. Due to the absence of dopants, an improvement of more than one order of magnitude in mobility (at 2 × 1011 cm−2) with respect to doped heterostructures with similar depths is observed. These undoped wafers can easily be gated with surface metallic gates patterned by e-beam lithography, as demonstrated here from single-level transport through a quantum dot showing large charging energies (up to 1.75 meV) and excited state energies (up to 0.5 meV).
Electrical readout of a spin qubit without double occupancy
Publisher: American Physical Society (APS)
Date: 23-03-2005
Metallic behaviour and localisation in 2D GaAs hole systems
Publisher: Elsevier BV
Date: 05-2013
Radio-frequency reflectometry on an undoped AlGaAs/GaAs single electron transistor
Publisher: AIP Publishing
Date: 06-01-2014
DOI: 10.1063/1.4858958
Abstract: Radio frequency reflectometry is demonstrated in a sub-micron undoped AlGaAs/GaAs device. Undoped single electron transistors (SETs) are attractive candidates to study single electron phenomena, due to their charge stability and robust electronic properties after thermal cycling. However, these devices require a large top-gate, which is unsuitable for the fast and sensitive radio frequency reflectometry technique. Here, we demonstrate that rf reflectometry is possible in an undoped SET.
Majorana zero modes in iron-based superconductors
Publisher: Elsevier BV
Date: 06-2022
The fabrication of devices in silicon using scanning probe microscopy
Publisher: SPIE
Date: 28-02-2005
DOI: 10.1117/12.582283
Maximizing the Hilbert space for a finite number of distinguishable quantum states
Publisher: American Physical Society (APS)
Date: 05-03-2004
Probing a single acceptor in a silicon nanotransistor
Publisher: IEEE
Date: 06-2014
Double-island single-electron transistor for noise-suppressed detection of charge transfer
Publisher: Elsevier BV
Date: 06-2003
<title>Nanoscale single-electron transistor architectures for single spin detection in solid state quantum computer devices</title>
Publisher: SPIE
Date: 19-11-2001
DOI: 10.1117/12.454622
Optimal operation points for ultrafast, highly coherent Ge hole spin-orbit qubits
Publisher: Springer Science and Business Media LLC
Date: 04-2021
DOI: 10.1038/S41534-021-00386-2
Abstract: Strong spin-orbit interactions make hole quantum dots central to the quest for electrical spin qubit manipulation enabling fast, low-power, scalable quantum computation. Yet it is important to establish to what extent spin-orbit coupling exposes qubits to electrical noise, facilitating decoherence. Here, taking Ge as an ex le, we show that group IV gate-defined hole spin qubits generically exhibit optimal operation points, defined by the top gate electric field, at which they are both fast and long-lived: the dephasing rate vanishes to first order in the electric field noise along with all directions in space, the electron dipole spin resonance strength is maximized, while relaxation is drastically reduced at small magnetic fields. The existence of optimal operation points is traced to group IV crystal symmetry and properties of the Rashba spin-orbit interaction unique to spin-3/2 systems. Our results overturn the conventional wisdom that fast operation implies reduced lifetimes and suggest group IV hole spin qubits as ideal platforms for ultra-fast, highly coherent scalable quantum computing.
The growth and characterisation of back-gated high mobility two-dimensional electron gas structures
Publisher: Elsevier BV
Date: 05-1993
Dreams Versus Reality: Plenary Debate Session on Quantum Computing
Publisher: Springer Science and Business Media LLC
Date: 12-2003
A self-aligned fabrication process for silicon quantum computer devices
Publisher: IOP Publishing
Date: 27-09-2002
Overlapping-Gate Architecture for Silicon Hall Bar MOSFET Devices in the Low Electron Density and High Magnetic Field Regime
Publisher: Trans Tech Publications, Ltd.
Date: 09-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.700.93
Abstract: A common issue in low temperature measurements of enhancement-mode metal-oxide-semiconductor (MOS) field-effect transistors (FETs) in the low electron density regime is the high contact resistance dominating the device impedance. In that case a voltage bias applied across the source and drain contact of a Hall bar MOSFET will mostly fall across the contacts (and not across the channel) and therefore magneto-transport measurements become challenging. However, from a physical point of view, the study of MOSFET nanostructures in the low electron density regime is very interesting (impurity limited mobility [1], carrier interactions [2,3] and spin-dependent transport [4]) and it is therefore important to come up with solutions [5,6] that work around the problem of a high contact resistance in such devices (c.f. Fig. 1 (a)).
Donor activation and damage in Si-SiO2 from low-dose, low-energy ion implantation studied via electrical transport in MOSFETs
Publisher: IOP Publishing
Date: 03-2005
Electric-field-induced charge noise in doped silicon: Ionization of phosphorus donors
Publisher: AIP Publishing
Date: 17-04-2006
DOI: 10.1063/1.2198013
Abstract: We report low-frequency charge noise measurement on silicon substrates with different phosphorus doping densities. The measurements are performed with aluminum single electron transistors (SETs) at millikelvin temperatures where the substrates are in the insulating regime. By measuring the SET Coulomb oscillations, we find a gate-voltage-dependent charge noise on the more heavily doped substrate. This charge noise is attributed to the electric-field-induced tunneling of electrons from their phosphorus donor potentials.
Quasi-one-dimensional transport in semiconductor microstructures
Publisher: IOP Publishing
Date: 1992
Nonlinear spin filter for nonmagnetic materials at zero magnetic field
Publisher: American Physical Society (APS)
Date: 21-10-2020
Impact of Small-Angle Scattering on Ballistic Transport in Quantum Dots
Publisher: American Physical Society (APS)
Date: 11-05-2012
Origin of the hysteresis in bilayer two-dimensional systems in the quantum Hall regime
Publisher: American Physical Society (APS)
Date: 13-10-2010
Use of low-temperature Hall effect to measure dopant activation: Role of electron-electron interactions
Publisher: American Physical Society (APS)
Date: 14-11-2007
Mapping the anisotropy of the Zeeman spin splitting of one-dimensional heavy holes in a GaAs quantum point contact
Publisher: IEEE
Date: 12-2014
(100) GaAs/Al(x)Ga(1-x)As heterostructures for Zeeman spin splitting studies of hole quantum wires
Publisher: Elsevier BV
Date: 05-2011
Is it the boundaries or disorder that dominates electron transport in semiconductor `billiards'?
Publisher: Wiley
Date: 18-06-2013
Abstract: Semiconductor billiards are often considered as ideal systems for studying dynamical chaos in the quantum mechanical limit. In the traditional picture, once the electron's mean free path, as determined by the mobility, becomes larger than the device, disorder is negligible and electron trajectories are shaped by specular reflection from the billiard walls alone. Experimental insight into the electron dynamics is normally obtained by magnetoconductance measurements. A number of recent experimental studies have shown these measurements to be largely independent of the billiard's exact shape, and highly dependent on s le‐to‐s le variations in disorder. In this paper, we discuss these more recent findings within the full historical context of work on semiconductor billiards, and offer strong evidence that small‐angle scattering at the sub‐100 nm length‐scale dominates transport in these devices. This has important implications for the role these devices can play for experimental tests of ideas in quantum chaos.
Role of background impurities in the single-particle relaxation lifetime of a two-dimensional electron gas
Publisher: American Physical Society (APS)
Date: 14-07-2009
New signatures of the spin gap in quantum point contacts
Publisher: Springer Science and Business Media LLC
Date: 04-01-2021
DOI: 10.1038/S41467-020-19895-3
Abstract: One dimensional semiconductor systems with strong spin-orbit interaction are both of fundamental interest and have potential applications to topological quantum computing. Applying a magnetic field can open a spin gap, a pre-requisite for Majorana zero modes. The spin gap is predicted to manifest as a field dependent dip on the first 1D conductance plateau. However, disorder and interaction effects make identifying spin gap signatures challenging. Here we study experimentally and numerically the 1D channel in a series of low disorder p-type GaAs quantum point contacts, where spin-orbit and hole-hole interactions are strong. We demonstrate an alternative signature for probing spin gaps, which is insensitive to disorder, based on the linear and non-linear response to the orientation of the applied magnetic field, and extract a spin-orbit gap Δ E ≈ 500 μ eV. This approach could enable one-dimensional hole systems to be developed as a scalable and reproducible platform for topological quantum applications.
Fabrication and characterization of an undoped GaAs single hole transistor
Publisher: IEEE
Date: 12-2010
Spin-Orbit Interaction in a Two-Dimensional Hole Gas at the Surface of Hydrogenated Diamond
Publisher: American Chemical Society (ACS)
Date: 08-12-2015
DOI: 10.1021/NL502081Y
Abstract: Hydrogenated diamond possesses a unique surface conductivity as a result of transfer doping by surface acceptors. Yet, despite being extensively studied for the past two decades, little is known about the system at low temperature, particularly whether a two-dimensional hole gas forms at the diamond surface. Here we report that (100) diamond, when functionalized with hydrogen, supports a p-type spin-3/2 two-dimensional surface conductivity with a spin-orbit interaction of 9.74 ± 0.1 meV through the observation of weak antilocalization effects in magneto-conductivity measurements at low temperature. Fits to 2D localization theory yield a spin relaxation length of 30 ± 1 nm and a spin-relaxation time of ∼ 0.67 ± 0.02 ps. The existence of a 2D system with spin orbit coupling at the surface of a wide band gap insulating material has great potential for future applications in ferromagnet-semiconductor and superconductor-semiconductor devices.
Narrow, highly P-doped, planar wires in silicon created by scanning probe microscopy
Publisher: IOP Publishing
Date: 12-12-2006
Double-layer-gate architecture for few-hole GaAs quantum dots
Publisher: IOP Publishing
Date: 08-07-2016
DOI: 10.1088/0957-4484/27/33/334001
Abstract: We report the fabrication of single and double hole quantum dots using a double-layer-gate design on an undoped accumulation mode [Formula: see text]/GaAs heterostructure. Electrical transport measurements of a single quantum dot show varying addition energies and clear excited states. In addition, the two-level-gate architecture can also be configured into a double quantum dot with tunable inter-dot coupling.
Spin polarization and spin-dependent scattering of holes observed in transverse magnetic focusing
Publisher: American Physical Society (APS)
Date: 12-01-2023
Determining the stability and activation energy of Si acceptors in AlGaAs using quantum interference in an open hole quantum dot
Publisher: American Physical Society (APS)
Date: 17-04-2014
Field-orientation dependence of the Zeeman spin splitting in (In,Ga)As quantum point contacts
Publisher: American Physical Society (APS)
Date: 12-01-2010
One-dimensional conduction properties of highly phosphorus-doped planar nanowires patterned by scanning probe microscopy
Publisher: American Physical Society (APS)
Date: 02-08-2007
Effect of screening long-range Coulomb interactions on the metallic behavior in two-dimensional hole systems
Publisher: American Physical Society (APS)
Date: 13-05-2008
Influence of doping density on electronic transport in degenerate Si:Pδ
Publisher: American Physical Society (APS)
Date: 03-01-2006
Observing sub-microsecond telegraph noise with the radio frequency single electron transistor
Publisher: AIP Publishing
Date: 22-11-2004
DOI: 10.1063/1.1813619
Abstract: Telegraph noise, which originates from the switching of charge between metastable trapping sites, becomes increasingly important as device sizes approach the nanoscale. For charge-based quantum computing, this noise may lead to decoherence and loss of readout fidelity. Here we use a radio frequency single electron transistor (rf-SET) to probe the telegraph noise present in a typical semiconductor-based quantum computer architecture. We frequently observe microsecond telegraph noise, which is a strong function of the local electrostatic potential defined by surface gate biases. We present a method for studying telegraph noise using the rf-SET and show results for a charge trap in which the capture and emission of a single electron is controlled by the bias applied to a surface gate.
Electrically detected magnetic resonance in ion-implanted Si : P nanostructures
Publisher: AIP Publishing
Date: 30-10-2006
DOI: 10.1063/1.2358928
Abstract: The authors present the results of electrically detected magnetic resonance (EDMR) experiments on ion-implanted Si:P nanostructures at 5K, consisting of high-dose implanted metallic leads with a square gap, in which phosphorus is implanted at a nonmetallic dose corresponding to 1017cm−3. By restricting this secondary implant to a 100×100nm2 region, the EDMR signal from less than 100 donors is detected. This technique provides a pathway to the study of single donor spins in semiconductors, which is relevant to a number of proposals for quantum information processing.
The 0.7 anomaly in one-dimensional hole quantum wires
Publisher: IOP Publishing
Date: 04-2008
Metallic behavior in low-disorder two-dimensional hole systems in the presence of long- and short-range disorder
Publisher: Elsevier BV
Date: 03-2008
Single atom Si nanoelectronics using controlled single-ion implantation
Publisher: Elsevier BV
Date: 03-2005
Pauli Spin Blockade of Heavy Holes in a Silicon Double Quantum Dot
Publisher: American Chemical Society (ACS)
Date: 12-10-2015
DOI: 10.1021/ACS.NANOLETT.5B02561
Abstract: In this work, we study hole transport in a planar silicon metal-oxide-semiconductor based double quantum dot. We demonstrate Pauli spin blockade in the few hole regime and map the spin relaxation induced leakage current as a function of interdot level spacing and magnetic field. With varied interdot tunnel coupling, we can identify different dominant spin relaxation mechanisms. Application of a strong out-of-plane magnetic field causes an avoided singlet-triplet level crossing, from which the heavy hole g-factor ~0.93 and the strength of spin-orbit interaction ~110 μeV can be obtained. The demonstrated strong spin-orbit interaction of heavy holes promises fast local spin manipulation using only electric fields, which is of great interest for quantum information processing.
Transport in disordered monolayer MoS2 nanoflakes-evidence for inhomogeneous charge transport
Publisher: IOP Publishing
Date: 22-08-2014
DOI: 10.1088/0957-4484/25/37/375201
Abstract: We study charge transport in a monolayer MoS2 nanoflake over a wide range of carrier density, temperature and electric bias. We find that the transport is best described by a percolating picture in which the disorder breaks translational invariance, breaking the system up into a series of puddles, rather than previous pictures in which the disorder is treated as homogeneous and uniform. Our work provides insight to a unified picture of charge transport in monolayer MoS2 nanoflakes and contributes to the development of next-generation MoS2-based devices.
Strong Spin-Orbit Contribution to the Hall Coefficient of Two-Dimensional Hole Systems
Publisher: American Physical Society (APS)
Date: 21-08-2018
Scanning probe microscopy for silicon device fabrication
Publisher: Informa UK Limited
Date: 05-2005
The fabrication of back-gated high electron mobility transistors — a novel approach using MBE regrowth on an in situ ion beam patterned epilayer
Publisher: Elsevier BV
Date: 02-1993
A Room‐Temperature Ferroelectric Resonant Tunneling Diode
Publisher: Wiley
Date: 02-08-2022
Abstract: Resonant tunneling is a quantum‐mechanical effect in which electron transport is controlled by the discrete energy levels within a quantum‐well (QW) structure. A ferroelectric resonant tunneling diode (RTD) exploits the switchable electric polarization state of the QW barrier to tune the device resistance. Here, the discovery of robust room‐temperature ferroelectric‐modulated resonant tunneling and negative differential resistance (NDR) behaviors in all‐perovskite‐oxide BaTiO 3 /SrRuO 3 /BaTiO 3 QW structures is reported. The resonant current litude and voltage are tunable by the switchable polarization of the BaTiO 3 ferroelectric with the NDR ratio modulated by ≈3 orders of magnitude and an OFF/ON resistance ratio exceeding a factor of 2 × 10 4 . The observed NDR effect is explained an energy bandgap between Ru‐t 2g and Ru‐e g orbitals driven by electron–electron correlations, as follows from density functional theory calculations. This study paves the way for ferroelectric‐based quantum‐tunneling devices in future oxide electronics.
Intra-Zero-Energy Landau Level Crossings in Bilayer Graphene at High Electric Fields
Publisher: American Chemical Society (ACS)
Date: 26-10-2023
Toward Atomic-Scale Device Fabrication in Silicon Using Scanning Probe Microscopy
Publisher: American Chemical Society (ACS)
Date: 28-09-2004
DOI: 10.1021/NL048808V
Dependence of the 0.7 anomaly on the curvature of the potential barrier in quantum wires
Publisher: American Physical Society (APS)
Date: 05-06-2015
Antisymmetric magnetoresistance in van der Waals Fe 3 GeTe 2 /graphite/Fe 3 GeTe 2 trilayer heterostructures
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-07-2019
Abstract: The observation of an antisymmetric magnetoresistance in a trilayer van der Waals heterostructure Fe 3 GeTe 2 /graphite/Fe 3 GeTe 2 .
Single-electron transistor architectures for charge motion detection in solid-state quantum computer devices
Publisher: IOP Publishing
Date: 20-09-2002
Localisation and the metal–insulator transition in two dimensions
Publisher: Elsevier BV
Date: 02-2001
Fabrication and characterization of few-hole quantum dots in undoped GaAs/AlGaAs heterostructures
Publisher: IEEE
Date: 12-2014
Charge-based quantum computing using single donors in semiconductors
Publisher: American Physical Society (APS)
Date: 11-03-2004
Spin–orbit coupling in silicon for electrons bound to donors
Publisher: Springer Science and Business Media LLC
Date: 23-11-2018
DOI: 10.1038/S41534-018-0111-1
Abstract: Spin–orbit coupling (SOC) is fundamental to a wide range of phenomena in condensed matter, spanning from a renormalisation of the free-electron g -factor, to the formation of topological insulators, and Majorana Fermions. SOC has also profound implications in spin-based quantum information, where it is known to limit spin lifetimes ( T 1 ) in the inversion asymmetric semiconductors such as GaAs. However, for electrons in silicon—and in particular those bound to phosphorus donor qubits—SOC is usually regarded weak, allowing for spin lifetimes of minutes in the bulk. Surprisingly, however, in a nanoelectronic device donor spin lifetimes have only reached values of seconds. Here, we reconcile this difference by demonstrating that electric field induced SOC can dominate spin relaxation of donor-bound electrons. Eliminating this lifetime-limiting effect by careful alignment of an external vector magnetic field in an atomically engineered device, allows us to reach the bulk-limit of spin-relaxation times. Given the unexpected strength of SOC in the technologically relevant silicon platform, we anticipate that our results will stimulate future theoretical and experimental investigation of phenomena that rely on strong magnetoelectric coupling of atomically confined spins.
Compressibility Measurements of Quasi-One-Dimensional Quantum Wires
Publisher: American Physical Society (APS)
Date: 13-09-2011
Atomically precise silicon device fabrication
Publisher: IEEE
Date: 08-2007
The electronic structure of a back-gated high electron mobility transistor
Publisher: IOP Publishing
Date: 03-1991
Progress in silicon-based quantum computing
Publisher: The Royal Society
Date: 15-07-2003
Abstract: We review progress at the Australian Centre for Quantum Computer Technology towards the fabrication and demonstration of spin qubits and charge qubits based on phosphorus donor atoms embedded in intrinsic silicon. Fabrication is being pursued via two complementary pathways: a 'top-down' approach for near-term production of few-qubit demonstration devices and a 'bottom-up' approach for large-scale qubit arrays with sub-nanometre precision. The 'top-down' approach employs a low-energy (keV) ion beam to implant the phosphorus atoms. Single-atom control during implantation is achieved by monitoring on-chip detector electrodes, integrated within the device structure. In contrast, the 'bottom-up' approach uses scanning tunnelling microscope lithography and epitaxial silicon overgrowth to construct devices at an atomic scale. In both cases, surface electrodes control the qubit using voltage pulses, and dual single-electron transistors operating near the quantum limit provide fast read-out with spurious-signal rejection.
Impact of long- and short-range disorder on the metallic behaviour of two-dimensional systems
Publisher: Springer Science and Business Media LLC
Date: 04-11-2008
DOI: 10.1038/NPHYS757
Multiband Mechanism for the Sign Reversal of Coulomb Drag Observed in Double Bilayer Graphene Heterostructures
Publisher: American Physical Society (APS)
Date: 17-07-2018
Electron-electron interactions in highly disordered two-dimensional systems
Publisher: American Physical Society (APS)
Date: 05-06-2008
Observation of the Kondo Effect in a Spin-3/2 Hole Quantum Dot
Publisher: AIP
Date: 2013
DOI: 10.1063/1.4848430
Frictional drag between parallel two-dimensional electron gases in a perpendicular magnetic field
Publisher: IOP Publishing
Date: 23-09-1996
Ohmic conduction of sub- 10 nm P-doped silicon nanowires at cryogenic temperatures
Publisher: AIP Publishing
Date: 04-02-2008
DOI: 10.1063/1.2840182
Abstract: We investigate the conduction properties of an embedded, highly phosphorus-doped nanowire with a width of 8nm lithographically defined by scanning tunneling microscope based patterning of a hydrogen-terminated Si(100):H surface. Four terminal I-V measurements show that ohmic conduction is maintained within the investigated temperature range from 35K down to 1.3K. A prominent resistance increase is observed below ∼4K which is attributed to a crossover into the strong localization regime. The low temperature conductance follows a one-dimensional variable range hopping model accompanied by positive magnetoresistance which dominates over weak localization effects at low temperature.
0.7 Structure and zero bias anomaly in one-dimensional hole systems
Publisher: Elsevier BV
Date: 03-2008
Radio-frequency reflectometry on large gated two-dimensional systems
Publisher: AIP Publishing
Date: 12-2008
DOI: 10.1063/1.3030860
Abstract: We have embedded an AlGaAs/GaAs based, gated two-dimensional (2D) hole system (2DHS) into an impedance transformer LC circuit and show that by using radio-frequency reflectometry it is possible to perform sensitive, large bandwidth, electrical resistance measurements of 2D systems at millikelvin temperatures. We construct a simple lumped element model where the gated 2DHS is described as a resistive transmission line. The model gives a qualitative understanding of the experimental results. As an ex le, we use our method to map out the Landau level evolution in a 2DHS as a function of magnetic field and gate voltage.
0.7 Structure and zero bias anomaly in ballistic hole quantum wires
Publisher: American Physical Society (APS)
Date: 10-01-2008
Electric Field Induced Charge Noise in Doped Silicon: Ionisation of Phosphorus Dopants
Publisher: AIP
Date: 2005
DOI: 10.1063/1.1994660
Piezoelectric rotator for studying quantum effects in semiconductor nanostructures at high magnetic fields and low temperatures
Publisher: AIP Publishing
Date: 11-2010
DOI: 10.1063/1.3502645
Abstract: We report the design and development of a piezoelectric s le rotation system, and its integration into an Oxford Instruments Kelvinox 100 dilution refrigerator, for orientation-dependent studies of quantum transport in semiconductor nanodevices at millikelvin temperatures in magnetic fields up to 10 T. Our apparatus allows for continuous in situ rotation of a device through & ° in two possible configurations. The first enables rotation of the field within the plane of the device, and the second allows the field to be rotated from in-plane to perpendicular to the device plane. An integrated angle sensor coupled with a closed-loop feedback system allows the device orientation to be known to within ±0.03° while maintaining the s le temperature below 100 mK.
Effects of biased and unbiased illuminations on two-dimensional electron gases in dopant-free GaAs/AlGaAs
Publisher: American Physical Society (APS)
Date: 07-02-2022
Combining n-MOS Charge Sensing with p-MOS Silicon Hole Double Quantum Dots in a CMOS platform
Publisher: American Chemical Society (ACS)
Date: 07-02-2023
AlGaAs/GaAs single electron transistor fabricated without modulation doping
Publisher: AIP Publishing
Date: 15-03-0011
DOI: 10.1063/1.3358388
Abstract: We have fabricated a quantum dot single electron transistor, based on AlGaAs/GaAs heterojunction without modulation doping, which exhibits clear and stable Coulomb blockade oscillations. The temperature dependence of the Coulomb blockade peak line shape is well described by standard Coulomb blockade theory in the quantum regime. Bias spectroscopy measurements have allowed us to directly extract the charging energy, and showed clear evidence of excited state transport, confirming that in idual quantum states in the dot can be resolved.
QUANTUM GLASS TRANSITION AT FINITE TEMPERATURE IN TWO-DIMENSIONAL ELECTRON LAYERS
Publisher: World Scientific Pub Co Pte Lt
Date: 05-11-2013
DOI: 10.1142/S0217979213470048
Abstract: We have investigated the formation of a quantum glass at finite temperatures in low-density two-dimensional conducting systems in semiconductor heterostructures. Using a memory function formalism we have determined the quantum glass melting curve for weak disorder as a function of density and temperature, and show that the glass-liquid transition is only weakly affected by increasing temperature at the least up to the Fermi temperature.
You need another gate, mate': G-factor engineering in quantum wires and wrap-gated nanowires
Publisher: IEEE
Date: 12-2012
Stacking of 2D Electron Gases in Ge Probed at the Atomic Level and Its Correlation to Low-Temperature Magnetotransport
Publisher: American Chemical Society (ACS)
Date: 04-09-2012
DOI: 10.1021/NL302558B
Abstract: Stacking of two-dimensional electron gases (2DEGs) obtained by δ-doping of Ge and patterned by scanning probe lithography is a promising approach to realize ultrascaled 3D epitaxial circuits, where multiple layers of active electronic components are integrated both vertically and horizontally. We use atom probe tomography and magnetotransport to correlate the real space 3D atomic distribution of dopants in the crystal with the quantum correction to the conductivity observed at low temperatures, probing if closely stacked δ-layers in Ge behave as independent 2DEGs. We find that at a separation of 9 nm the stacked-2DEGs, while interacting, still maintain their in iduality in terms of electron transport and show long phase coherence lengths (∼220 nm). Strong vertical electron confinement is crucial to this finding, resulting in an interlayer scattering time much longer (∼1000 × ) than the scattering time within the dopant plane.
Single electron devices for simulating read-out in a solid state quantum computer
Publisher: Elsevier BV
Date: 06-2003
Fabrication of induced two-dimensional hole systems on (311)A GaAs
Publisher: AIP Publishing
Date: 15-01-2006
DOI: 10.1063/1.2163998
Abstract: We demonstrate a method for fabricating induced two-dimensional hole devices in (311)A GaAs. The method uses a metallic p+-GaAs capping layer as an in situ top gate that pins the Fermi energy close to the valence band, thereby allowing very small gate biases to be used to induce a two-dimensional hole system at a AlGaAs∕GaAs interface. We present transport data from devices with different levels of background impurities. Modeling the mobility as a function of hole density gives a quantitative measure of the level of disorder and indicates that these systems can be used for a systematic study of the effects of disorder in strongly interacting low-dimensional systems.
Stability of the bilayer ν=1 quantum Hall state under charge imbalance
Publisher: Elsevier BV
Date: 04-2004
Screening long-range Coulomb interactions in 2D hole systems using a bilayer heterostructure
Publisher: Elsevier BV
Date: 03-2008
Electrical control of the sign of the g factor in a GaAs hole quantum point contact
Publisher: American Physical Society (APS)
Date: 18-07-2016
Fabrication and characterisation of gallium arsenide ambipolar quantum point contacts
Publisher: AIP Publishing
Date: 04-05-2015
DOI: 10.1063/1.4918934
Abstract: We show that ballistic one-dimensional channels can be formed in an ambipolar device fabricated on a high mobility Al0.34Ga0.66As/GaAs heterostructure. Both electron and hole quantised conductances can be measured in the same one-dimensional channel. We have used this device to compare directly the subband spacings of the two charge carriers in the same confining potential and used this to compare the electron and hole effective masses.
Measurements of a composite fermion split-gate
Publisher: Elsevier BV
Date: 07-1996
Lightly strained germanium quantum wells with hole mobility exceeding one million
Publisher: AIP Publishing
Date: 21-03-2022
DOI: 10.1063/5.0083161
Abstract: We demonstrate that a lightly strained germanium channel (ε//=−0.41%) in an undoped Ge/Si0.1Ge0.9 heterostructure field effect transistor supports a two-dimensional (2D) hole gas with mobility in excess of 1×106 cm2/Vs and percolation density less than 5×1010 cm−2. This low disorder 2D hole system shows tunable fractional quantum Hall effects at low densities and low magnetic fields. The low-disorder and small effective mass (0.068me) defines lightly strained germanium as a basis to tune the strength of the spin–orbit coupling for fast and coherent quantum hardware.
Anisotropic Pauli Spin Blockade of Holes in a GaAs Double Quantum Dot
Publisher: American Chemical Society (ACS)
Date: 12-2016
DOI: 10.1021/ACS.NANOLETT.6B03752
Abstract: Electrically defined semiconductor quantum dots are attractive systems for spin manipulation and quantum information processing. Heavy-holes in both Si and GaAs are promising candidates for all-electrical spin manipulation, owing to the weak hyperfine interaction and strong spin-orbit interaction. However, it has only recently become possible to make stable quantum dots in these systems, mainly due to difficulties in device fabrication and stability. Here, we present electrical transport measurements on holes in a gate-defined double quantum dot in a GaAs/Al
Anodic oxidation of epitaxial superconductor-semiconductor hybrids
Publisher: American Physical Society (APS)
Date: 25-01-2021
Extreme Sensitivity of the Spin-Splitting and 0.7 Anomaly to Confining Potential in One-Dimensional Nanoelectronic Devices
Publisher: American Chemical Society (ACS)
Date: 08-2012
DOI: 10.1021/NL301566D
Abstract: Quantum point contacts (QPCs) have shown promise as nanoscale spin-selective components for spintronic applications and are of fundamental interest in the study of electron many-body effects such as the 0.7 × 2e(2)/h anomaly. We report on the dependence of the 1D Landé g-factor g and 0.7 anomaly on electron density and confinement in QPCs with two different top-gate architectures. We obtain g values up to 2.8 for the lowest 1D subband, significantly exceeding previous in-plane g-factor values in AlGaAs/GaAs QPCs and approaching that in InGaAs/InP QPCs. We show that g is highly sensitive to confinement potential, particularly for the lowest 1D subband. This suggests careful management of the QPC's confinement potential may enable the high g desirable for spintronic applications without resorting to narrow-gap materials such as InAs or InSb. The 0.7 anomaly and zero-bias peak are also highly sensitive to confining potential, explaining the conflicting density dependencies of the 0.7 anomaly in the literature.
Geometric Control of Universal Hydrodynamic Flow in a Two-Dimensional Electron Fluid
Publisher: American Physical Society (APS)
Date: 06-08-2021
Single particle and momentum relaxation times in two-dimensional electron systems
Publisher: SPIE
Date: 21-12-2008
DOI: 10.1117/12.759655
Scaling of coherent tunneling adiabatic passage in solid-state coherent quantum systems.
Publisher: SPIE
Date: 23-02-2005
DOI: 10.1117/12.583193
Observation of the Kondo effect in a spin-3/2 hole quantum dot
Publisher: IEEE
Date: 12-2012
Conductance quantisation in an induced hole quantum wire
Publisher: AIP
Date: 2007
DOI: 10.1063/1.2730073
Theory of hole-spin qubits in strained germanium quantum dots
Publisher: American Physical Society (APS)
Date: 15-03-2021
Electrical properties of atomically controlled Si:P nanowires created by scanning probe microscopy
Publisher: AIP
Date: 2007
DOI: 10.1063/1.2730076
Detection and Control of Spin-Orbit Interactions in a GaAs Hole Quantum Point Contact
Publisher: American Physical Society (APS)
Date: 05-04-2017
Bottom-up assembly of metallic germanium
Publisher: Springer Science and Business Media LLC
Date: 10-08-2015
DOI: 10.1038/SREP12948
Abstract: Extending chip performance beyond current limits of miniaturisation requires new materials and functionalities that integrate well with the silicon platform. Germanium fits these requirements and has been proposed as a high-mobility channel material, a light emitting medium in silicon-integrated lasers and a plasmonic conductor for bio-sensing. Common to these erse applications is the need for homogeneous, high electron densities in three-dimensions (3D). Here we use a bottom-up approach to demonstrate the 3D assembly of atomically sharp doping profiles in germanium by a repeated stacking of two-dimensional (2D) high-density phosphorus layers. This produces high-density (10 19 to 10 20 cm −3 ) low-resistivity (10 −4 Ω · cm) metallic germanium of precisely defined thickness, beyond the capabilities of diffusion-based doping technologies. We demonstrate that free electrons from distinct 2D dopant layers coalesce into a homogeneous 3D conductor using anisotropic quantum interference measurements, atom probe tomography and density functional theory.
High-Temperature Superfluidity in Double-Bilayer Graphene
Publisher: American Physical Society (APS)
Date: 03-04-2013
Ballistic induced hole quantum wires fabricated on a (1 0 0)-oriented AlGaAs/GaAs heterostructure
Publisher: Elsevier BV
Date: 02-2010
An Improved Process for Fabricating High-Mobility Organic Molecular Crystal Field-Effect Transistors
Publisher: IEEE
Date: 2006
Correlated charge detection for readout of a solid-state quantum computer
Publisher: AIP Publishing
Date: 22-01-2003
DOI: 10.1063/1.1539904
Abstract: The single-electron transistor (SET) is a prime candidate for reading out the final state of a qubit in a solid-state quantum computer. Such a measurement requires the detection of subelectron charge motion in the presence of random charging events. We present a detection scheme where the signals from two SETs are cross-correlated to suppress unwanted artifacts due to charge noise. This technique is demonstrated by using the two SETs to detect the charge state of two coupled metal dots, thereby simulating charge transfer and readout in a two-qubit system. These measurements indicate that for comparable buried dopant semiconductor architectures, the minimum measurement time required to distinguish between the two charge states is of the order of 10 ns.
Overlapping-gate architecture for silicon Hall bar field-effect transistors in the low electron density regime
Publisher: AIP Publishing
Date: 11-10-2010
DOI: 10.1063/1.3501136
Abstract: We report the fabrication and study of Hall bar field-effect transistors in which an overlapping-gate architecture allows four-terminal measurements of low-density two-dimensional electron systems while maintaining a high density at the Ohmic contacts. Comparison with devices made using a standard single gate show that measurements can be performed at much lower densities and higher channel resistances, despite a reduced peak mobility. We also observe a voltage threshold shift which we attribute to negative oxide charge, injected during electron-beam lithography processing.
Electrical Control of the Zeeman Spin Splitting in Two-Dimensional Hole Systems
Publisher: American Physical Society (APS)
Date: 15-08-2018
The origin of gate hysteresis in p-type Si-doped AlGaAs/GaAs heterostructures
Publisher: IEEE
Date: 12-2012
g-factor and well-width fluctuations as a function of carrier density in the two-dimensional hole accumulation layer of transfer-doped diamond
Publisher: American Physical Society (APS)
Date: 29-01-2019
Fabrication and characterization of an induced GaAs single hole transistor
Publisher: AIP Publishing
Date: 03-2010
DOI: 10.1063/1.3336011
Abstract: We have fabricated and characterized a single hole transistor in an undoped AlGaAs-GaAs heterostructure. Our device consists of a p-type quantum dot, populated using an electric field rather than modulation doping. Low temperature transport measurements reveal periodic conductance oscillations due to Coulomb blockade. We find that the low frequency charge noise is comparable to that in modulation-doped GaAs single electron transistors (SETs), and an order of magnitude better than in silicon SETs.
Experimental conditions for the observation of electron-hole superfluidity in GaAs heterostructures
Publisher: American Physical Society (APS)
Date: 06-04-2020
Ultra‐Shallow All‐Epitaxial Aluminum Gate GaAs/AlxGa1−xAs Transistors with High Electron Mobility
Publisher: Wiley
Date: 19-08-2022
Abstract: The electron mobility in shallow GaAs/Al x Ga 1−x As heterostructures is strongly suppressed by charge wafer surface, which arises from native surface oxide layers formed when the wafer is removed from the crystal growth system. Here an in situ epitaxial aluminum gate, grown as part of the wafer, is used to eliminate surface charge scattering. Transmission electron microscope characterization shows that the in situ epitaxial aluminum is crystalline, and the wafer surface is free of native oxide. The influence of Al thickness and the use of different semiconductor wetting layers at the semiconductor‐aluminum interface are examined and correlated with electron mobility. The electron mobility is found to strongly depend on aluminum thickness. For 8 nm thick aluminum, the electron mobility is also influenced by the wetting layer, with aluminum grown on GaAs producing higher mobility compared to AlAs or Al 0.33 Ga 0.67 As wetting layers. The suppression of surface charge scattering in these all‐epitaxial devices allows for high mobilities across a wide density range despite the shallow conduction channel (35 nm below the gate). These measurements also provide a uniquely sensitive method of determining the electrical quality of the semiconductor–metal interface, relevant to the formation of hybrid semiconductor–superconductor devices.
Observation of single hole transport in a highly tunable silicon quantum dot
Publisher: IEEE
Date: 12-2014
Decoding the ternary Golay code
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-1993
DOI: 10.1109/18.256511
Realization of Atomically Controlled Dopant Devices in Silicon
Publisher: Wiley
Date: 22-03-2007
Two-dimensional lateral surface superlattices in GaAs heterostructures with independent control of carrier density and modulation potential
Publisher: AIP Publishing
Date: 20-07-2020
DOI: 10.1063/5.0009462
Abstract: We present a double-layer design for two-dimensional lateral surface superlattice systems in GaAs-AlGaAs heterostructures. Unlike previous studies, our device (1) uses an in situ gate, which allows a very short period superlattice in high mobility, shallow heterostructures and (2) enables independent control of the carrier density and the superlattice modulation potential litude over a wide range. We characterize this device design using low-temperature magneto-transport measurements and show that the fabrication process caused minimal damage to the system. We demonstrate the tuning of potential modulation from weak (much smaller than Fermi energy) to strong (larger than the Fermi energy) regimes.
The interplay between one-dimensional confinement and two-dimensional crystallographic anisotropy effects in ballistic hole quantum wires
Publisher: IOP Publishing
Date: 15-04-2009
Using a Tunable Quantum Wire To Measure the Large out-of-Plane Spin Splitting of Quasi Two-Dimensional Holes in a GaAs Nanostructure
Publisher: American Chemical Society (ACS)
Date: 26-12-2013
DOI: 10.1021/NL303596S
Abstract: The out-of-plane g-factor g([perpendicular])(*) for quasi two-dimensional (2D) holes in a (100) GaAs heterostructure is studied using a variable width quantum wire. A direct measurement of the Zeeman splitting is performed in a magnetic field applied perpendicular to the 2D plane. We measure an out-of-plane g-factor up to g([perpendicular])(*) = 5, which is larger than previous optical studies of g([perpendicular])(*) and is approaching the long predicted but never experimentally verified out-of-plane g-factor of 7.2 for heavy holes.
Development and operation of the twin radio frequency single electron transistor for cross-correlated charge detection
Publisher: AIP Publishing
Date: 04-10-2004
DOI: 10.1063/1.1786671
Abstract: Ultrasensitive detectors and readout devices based on the radio frequency single electron transistor (rf-SET) combine near quantum-limited sensitivity with fast operation. Here we describe a twin rf-SET detector that uses two superconducting rf-SETs to perform fast, real-time cross-correlated measurements in order to distinguish subelectron signals from charge noise on microsecond time scales. The twin rf-SET makes use of two tuned resonance circuits to simultaneously and independently address both rf-SETs using wavelength ision multiplexing and a single cryogenic lifier. We focus on the operation of the twin rf-SET as a charge detector and evaluate the cross talk between the two resonance circuits. Real-time suppression of charge noise is demonstrated by cross correlating the signals from the two rf-SETs. For the case of simultaneous operation, the rf-SETs had charge sensitivities of δqSET1=7.5μe∕Hz and δqSET2=4.4μe∕Hz.
Charge transport by modulating spin-orbit gauge fields for quasi-one-dimensional holes
Publisher: AIP Publishing
Date: 11-04-2011
DOI: 10.1063/1.3579197
Abstract: We present a theoretical study of ac charge transport arising from adiabatic temporal variation of zero-field spin splitting in a quasi-one-dimensional hole system (realized, e.g., in a quantum wire or point contact). As in conduction-electron systems, part of the current results from spin-dependent electromotive forces. We find that the magnitude of this current contribution is two orders of magnitude larger for holes and exhibits parametric dependences that make it more easily accessible experimentally. Our results suggest hole structures to be good candidates for realizing devices where spin currents are pumped by time-varying electric fields.
Quantum tunnelling and hopping between metallic domains in disordered two-dimensional mesoscopic electron systems
Publisher: IOP Publishing
Date: 08-05-2009
Observation of the Kondo Effect in a Spin-3/2 Hole Quantum Dot
Publisher: American Physical Society (APS)
Date: 12-08-2011
Anisotropic Zeeman Splitting In Ballistic One-Dimensional Hole Systems
Publisher: AIP
Date: 2007
DOI: 10.1063/1.2730082
Modelling of electrostatic gate operations in the Kane solid state quantum computer
Publisher: Elsevier BV
Date: 12-2002
Weak localization in high-quality two-dimensional systems
Publisher: American Physical Society (APS)
Date: 14-12-2004
Chester Supersolid of Spatially Indirect Excitons in Double-Layer Semiconductor Heterostructures
Publisher: American Physical Society (APS)
Date: 02-2023
Influence of surface states on quantum and transport lifetimes in high-quality undoped heterostructures
Publisher: American Physical Society (APS)
Date: 23-05-2013
Transverse magnetic focussing of heavy holes in a (100) GaAs quantum well
Publisher: IOP Publishing
Date: 14-09-2015
Excitonic superfluidity and screening in electron-hole bilayer systems
Publisher: American Physical Society (APS)
Date: 18-02-2014
Electron–hole superfluidity in strained Si/Ge type II heterojunctions
Publisher: Springer Science and Business Media LLC
Date: 23-04-2021
DOI: 10.1038/S41535-021-00344-3
Abstract: Excitons are promising candidates for generating superfluidity and Bose–Einstein condensation (BEC) in solid-state devices, but an enabling material platform with in-built band structure advantages and scaling compatibility with industrial semiconductor technology is lacking. Here we predict that spatially indirect excitons in a lattice-matched strained Si/Ge bilayer embedded into a germanium-rich SiGe crystal would lead to observable mass-imbalanced electron–hole superfluidity and BEC. Holes would be confined in a compressively strained Ge quantum well and electrons in a lattice-matched tensile strained Si quantum well. We envision a device architecture that does not require an insulating barrier at the Si/Ge interface, since this interface offers a type II band alignment. Thus the electrons and holes can be kept very close but strictly separate, strengthening the electron–hole pairing attraction while preventing fast electron–hole recombination. The band alignment also allows a one-step procedure for making independent contacts to the electron and hole layers, overcoming a significant obstacle to device fabrication. We predict superfluidity at experimentally accessible temperatures of a few Kelvin and carrier densities up to ~6 × 10 10 cm −2 , while the large imbalance of the electron and hole effective masses can lead to exotic superfluid phases.
Probing the Spin States of a Single Acceptor Atom
Publisher: American Chemical Society (ACS)
Date: 03-03-2014
DOI: 10.1021/NL4047015
Abstract: We demonstrate a single-hole transistor using an in idual acceptor dopant embedded in a silicon channel. Magneto-transport spectroscopy reveals that the ground state splits as a function of magnetic field into four states, which is unique for a single hole bound to an acceptor in a bulk semiconductor. The two lowest spin states are heavy (|m(j)| = 3/2) and light (|m(j)| = 1/2) hole-like, a two-level system that can be electrically driven and is characterized by a magnetic field dependent and long relaxation time, which are properties of interest for qubits. Although the bulklike spin splitting of a boron atom is preserved in our nanotransistor, the measured Landé g-factors, |g(hh)| = 0.81 ± 0.06 and |g(lh)| = 0.85 ± 0.21 for heavy and light holes respectively, are lower than the bulk value.
Single hole transport in a silicon metal-oxide-semiconductor quantum dot
Publisher: AIP Publishing
Date: 14-10-2013
DOI: 10.1063/1.4826183
Abstract: We describe a planar silicon metal-oxide-semiconductor (MOS) based single hole transistor, which is compatible with conventional Si complementary MOS fabrication. A multi-layer gate design gives independent control of the carrier density in the dot and reservoirs. Clear Coulomb blockade oscillations are observed, and source-drain biasing measurements show that it is possible to deplete the dot down to the few hole regime, with excited states clearly visible. The architecture is sufficiently versatile that a second hole dot could be induced adjacent to the first one.
The fate of quantum Hall extended states as B→0 and the possibility of a 2D metal
Publisher: Elsevier BV
Date: 2002
The growth of high mobility heterostructures on (311)B GaAs
Publisher: Elsevier BV
Date: 12-1995
Fabrication of Undoped AlGaAs/GaAs Electron Quantum Dots
Publisher: AIP
Date: 2011
DOI: 10.1063/1.3666394
The use of etched registration markers to make four-terminal electrical contacts to STM-patterned nanostructures
Publisher: IOP Publishing
Date: 02-09-2005
DOI: 10.1088/0957-4484/16/10/076
Abstract: We demonstrate the use of etched registration markers for the alignment of four-terminal ex situ macroscopic contacts created by conventional optical lithography to buried nanoscale Si:P devices, patterned by hydrogen-based scanning tunnelling microscope (STM) lithography. Using SiO(2) as a mask we are able to protect the silicon surface from contamination during marker fabrication and can achieve atomically flat surfaces with atomic-resolution imaging. The registration markers are shown to withstand substrate heating to approximately 1200 degrees C and epitaxial overgrowth of approximately 25 nm Si. Using a scanning electron microscope to position the STM tip with respect to the markers, we can achieve alignment accuracies of approximately 100 nm, which allows us to contact buried Si:P structures. We have applied this technique to fabricate P-doped wires of different widths and measured their I-V characteristics at 4 K, finding ohmic behaviour down to a width of approximately 27 nm.
A High‐Mobility Hole Bilayer in a Germanium Double Quantum Well
Publisher: Wiley
Date: 25-03-2022
Abstract: A hole bilayer in a strained germanium double quantum well is designed, fabricated, and studied. Magnetotransport characterization of double quantum well field‐effect transistors as a function of gate voltage reveals the population of two hole channels with a high combined mobility of and a low percolation density of . The in idual population of the channels from the interference patterns of the Landau fan diagram was resolved. At a density of the system is in resonance and an anti‐crossing of the first two bilayer subbands is observed and a symmetric‐antisymmetric gap of is estimated, in agreement with Schrödinger‐Poisson simulations.
Evolution of the bilayer ν= 1 quantum Hall state under charge imbalance
Publisher: American Physical Society (APS)
Date: 10-02-2005
Fabrication and characterisation of an induced ambipolar device on AlGaAs/GaAs Heterostructures
Publisher: IEEE
Date: 12-2010
The influence of small-angle scattering on ballistic transport in quantum dots
Publisher: IEEE
Date: 12-2012
The 1D g-factor and 0.7 anomaly in QPCs with independent control over density
Publisher: IEEE
Date: 12-2012
A room-temperature ferroelectric semimetal
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-07-2019
Abstract: WTe 2 , a layered crystalline material, displays both ferroelectricity and metallicity.
Gate voltage dependent Rashba spin splitting in hole transverse magnetic focusing
Publisher: American Physical Society (APS)
Date: 15-06-2022
Fabrication and characterization of a 2D hole system a in novel (311)A GaAs SISFET
Publisher: Elsevier BV
Date: 03-2005
Integer quantum Hall states in coupled double electron gas systems at mismatched carrier densities
Publisher: IOP Publishing
Date: 27-05-1996
Electrometry using the quantum Hall effect in a bilayer two-dimensional electron system
Publisher: AIP Publishing
Date: 24-05-2010
DOI: 10.1063/1.3428778
Abstract: We discuss the development of a sensitive electrometer that utilizes a two-dimensional electron gas (2DEG) in the quantum Hall regime. As a demonstration, we measure the evolution of the Landau levels in a second, nearby 2DEG as the applied perpendicular magnetic field is changed, and extract an effective mass for electrons in GaAs that agrees within experimental error with previous measurements.
Zeeman Splitting in Ballistic Hole Quantum Wires
Publisher: American Physical Society (APS)
Date: 11-07-2006
Exchange-driven bilayer-to-monolayer charge transfer in an asymmetric double-quantum-well
Publisher: Elsevier BV
Date: 2002
Confinement properties of aGa 0.25
Publisher:
American Physical Society (APS)
Date:
08-04-2008
Publisher: American Physical Society (APS)
Date: 08-04-2008
Anomalous transport in mesoscopic inhomogeneous two-dimensional electron systems at low temperature
Publisher: American Physical Society (APS)
Date: 20-07-2010
Novel annealing processes for soluble acenes
Publisher: IEEE
Date: 02-2010
Quantum-dot cellular automata: introduction and experimental overview
Publisher: IEEE
Date: 2001
Mechanisms for Strong Anisotropy of In-Plane g-Factors in Hole Based Quantum Point Contacts
Publisher: American Physical Society (APS)
Date: 12-09-2017
Nuclear magnetic resonance in GaAs-AlGaAs nanostructure devices
Publisher: IEEE
Date: 12-2010
Conductance quantization and the 0.7×2e2/h conductance anomaly in one-dimensional hole systems
Publisher: AIP Publishing
Date: 02-01-2006
DOI: 10.1063/1.2161814
Abstract: We have studied ballistic transport in a one-dimensional (1D) channel formed using surface gate techniques on a back-gated, high-mobility, bilayer two-dimensional hole system. At millikelvin temperatures, robust conductance quantization is observed in the quantum wire formed in the top layer of the bilayer system, without the gate instabilities that have h ered previous studies of 1D hole systems. Using source drain bias spectroscopy, we have measured the 1D subband spacings, which are 5–10 times smaller than in comparable GaAs electron systems, but 2–3 times larger than in previous studies of 1D holes. We also report the first observation of the anomalous conductance plateau at G=0.7×2e2∕h in a 1D hole system.
Using light and heat to controllably switch and reset disorder configuration in nanoscale devices
Publisher: American Physical Society (APS)
Date: 19-02-2015
Electronic properties of atomically abrupt tunnel junctions in silicon
Publisher: American Physical Society (APS)
Date: 21-03-2007
Metallic Behavior in Dilute Two-Dimensional Hole Systems
Publisher: American Physical Society (APS)
Date: 29-08-2001
Noncollinear Paramagnetism of a GaAs Two-Dimensional Hole System
Publisher: American Physical Society (APS)
Date: 03-12-2014
Zero-Energy Modes from Coalescing Andreev States in a Two-Dimensional Semiconductor-Superconductor Hybrid Platform
Publisher: American Physical Society (APS)
Date: 26-10-2017
The reduced effective interaction parameter in closely spaced two-dimensional hole systems
Publisher: AIP
Date: 2009
DOI: 10.1063/1.3295372
Formation of Artificial Fermi Surfaces with a Triangular Superlattice on a Conventional Two-Dimensional Electron Gas
Publisher: American Chemical Society (ACS)
Date: 15-02-2023
Fabrication of undoped AlGaAs/GaAs electron quantum dots
Publisher: IEEE
Date: 02-2010
Three-dimensional electron-hole superfluidity in a superlattice close to room temperature
Publisher: American Physical Society (APS)
Date: 25-08-2020
A study of transport suppression in an undoped AlGaAs/GaAs quantum dot single-electron transistor
Publisher: IOP Publishing
Date: 25-11-2013
DOI: 10.1088/0953-8984/25/50/505302
Abstract: We report a study of transport blockade features in a quantum dot single-electron transistor, based on an undoped AlGaAs/GaAs heterostructure. We observe suppression of transport through the ground state of the dot, as well as negative differential conductance at finite source-drain bias. The temperature and magnetic field dependences of these features indicate the couplings between the leads and the quantum dot states are suppressed. We attribute this to two possible mechanisms: spin effects which determine whether a particular charge transition is allowed based on the change in total spin, and the interference effects which arise from coherent tunnelling of electrons in the quantum dot.
Superconductivity in metal-mixed ion-implanted polymer films
Publisher: AIP Publishing
Date: 09-10-2006
DOI: 10.1063/1.2358190
Abstract: Ion implantation of normally insulating polymers offers an alternative to depositing conjugated organics onto plastic films to make electronic circuits. We used a 50keV nitrogen ion beam to mix a thin 10nm Sn∕Sb alloy film into the subsurface of polyetheretherketone and report the low temperature properties of this material. We observed metallic behavior, and the onset of superconductivity below 3K. There are strong indications that the superconductivity does not result from a residual thin film of alloy, but instead from a network of alloy grains coupled via a weakly conducting, ion-beam carbonized polymer matrix.
Low temperature transport on surface conducting diamond
Publisher: IEEE
Date: 12-0002
Signatures of quantum mechanical Zeeman effect in classical transport due to topological properties of two-dimensional spin-
Publisher:
American Physical Society (APS)
Date:
09-03-2020
Publisher: American Physical Society (APS)
Date: 09-03-2020
DREAMS VERSUS REALITY: PLENARY DEBATE SESSION ON QUANTUM COMPUTING
Publisher: World Scientific Pub Co Pte Lt
Date: 06-2008
Single-shot readout with the radio-frequency single-electron transistor in the presence of charge noise
Publisher: AIP Publishing
Date: 04-2005
DOI: 10.1063/1.1897423
Abstract: The radio-frequency single-electron transistor (rf-SET) possesses key requirements necessary for reading out a solid state quantum computer. This work explores the use of the rf-SET as a single-shot readout device in the presence of 1∕f and telegraph charge noise. For a typical spectrum of 1∕f noise we find that high fidelity, single-shot measurements are possible for signals Δq& .01e. For the case of telegraph noise, we present a cross-correlation measurement technique that uses two rf-SETs to suppress the effect of random switching events on readout. We demonstrate this technique by monitoring the charge state of a metal double dot system on microsecond time scales. Such a scheme will be advantageous in achieving high readout fidelity in a solid-state quantum computer.
Nanofabrication of charge-based Si:P quantum computer devices using single-ion implantation
Publisher: SPIE
Date: 23-02-2005
DOI: 10.1117/12.583284
Current suppression in a double-island single-electron transistor for detection of degenerate charge configurations of a floating double-dot
Publisher: AIP Publishing
Date: 24-11-2003
DOI: 10.1063/1.1630382
Abstract: We have investigated a double-island single-electron transistor (DISET) coupled to a floating metal double-dot (DD). Low-temperature transport measurements were used to map out the charge configurations of both the DISET and the DD. A suppression of the current through the DISET was observed whenever the charge configurations of the DISET and the DD were energetically codegenerate. This effect was used to distinguish between degenerate and nondegenerate charge configurations of the DD. We also show that this detection scheme reduces the susceptibility of the DISET to interference from random charge noise.
Effect of encapsulation temperature on Si:P δ-doped layers
Publisher: AIP Publishing
Date: 22-11-2004
DOI: 10.1063/1.1827940
Abstract: We present a systematic study of the effect of encapsulation temperature on dopant segregation and electronic transport in Si:P δ-doped layers. We demonstrate that while limited dopant segregation and complete electrical activation can be achieved at room temperature, a δ-doped layer encapsulated at ∼250°C represents the best compromise between high electrical quality (mobility ∼61cm2V−1s−1 and phase coherence length ∼72nm at 4.2K) and minimal dopant segregation. Higher encapsulation temperatures are shown to lead to significant dopant segregation.
Quantum transport in one-dimensional GaAs hole systems
Publisher: Inderscience Publishers
Date: 2008
Optimizing topological switching in confined 2D-Xene nanoribbons via finite-size effects
Publisher: AIP Publishing
Date: 26-01-2022
DOI: 10.1063/5.0076625
Abstract: In a blueprint for topological electronics, edge state transport in a topological insulator material can be controlled by employing a gate-induced topological quantum phase transition. Here, by studying the width dependence of electronic properties, it is inferred that zigzag-Xene nanoribbons are promising materials for topological electronics with a display of unique physical characteristics associated with the intrinsic band topology and the finite-size effects on gate-induced topological switching. First, due to intertwining with intrinsic band topology-driven energy-zero modes in the pristine case, spin-filtered chiral edge states in zigzag-Xene nanoribbons remain gapless and protected against backward scattering even with finite inter-edge overlapping in ultra-narrow ribbons, i.e., a 2D quantum spin Hall material turns into a 1D topological metal. Second, mainly due to width- and momentum-dependent tunability of the gate-induced inter-edge coupling, the threshold-voltage required for switching between gapless and gapped edge states reduces as the width decreases, without any fundamental lower bound. Third, when the width of zigzag-Xene nanoribbons is smaller than a critical limit, topological switching between edge states can be attained without bulk bandgap closing and reopening. This is primarily due to the quantum confinement effect on the bulk band spectrum, which increases the nontrivial bulk bandgap with decrease in width. The existence of such protected gapless edge states and reduction in threshold-voltage accompanied by enhancement in the bulk bandgap overturns the general wisdom of utilizing narrow-gap and wide channel materials for reducing the threshold-voltage in a standard field effect transistor analysis and paves the way toward low-voltage topological devices.
Electrical Characterization of Ordered Si:P Dopant Arrays
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2007
Atomic-scale silicon device fabrication
Publisher: Inderscience Publishers
Date: 2008
The twin radio frequency single electron transistor for correlated charge detection on microsecond time-scales
Publisher: Elsevier BV
Date: 06-2003
Electrically controlled piezo-rotator for studying semiconductor nanostructures at milli-Kelvin temperatures and high magnetic fields
Publisher: IEEE
Date: 02-2010
Controlled single electron transfer between Si:P dots
Publisher: AIP Publishing
Date: 08-05-0001
DOI: 10.1063/1.2203740
Abstract: We demonstrate electrical control of Si:P double dots in which the potential is defined by nanoscale phosphorus-doped regions. Each dot contains approximately 600 phosphorus atoms and has a diameter close to 30nm. On application of a differential bias across the dots, electron transfer is observed, using single electron transistors in both dc and rf modes as charge detectors. With the possibility to scale the dots down to a few and even single atoms these results open the way to a new class of precision-doped quantum dots in silicon.
Strong and tunable spin-orbit coupling in a two-dimensional hole gas in ionic-liquid gated diamond devices
Publisher: American Chemical Society (ACS)
Date: 26-05-2016
DOI: 10.1021/ACS.NANOLETT.6B01155
Abstract: Hydrogen-terminated diamond possesses due to transfer doping a quasi-two-dimensional (2D) hole accumulation layer at the surface with a strong, Rashba-type spin-orbit coupling that arises from the highly asymmetric confinement potential. By modulating the hole concentration and thus the potential using an electrostatic gate with an ionic-liquid dielectric architecture the spin-orbit splitting can be tuned from 4.6-24.5 meV with a concurrent spin relaxation length of 33-16 nm and hole sheet densities of up to 7.23 × 10(13) cm(-2). This demonstrates a spin-orbit interaction of unprecedented strength and tunability for a 2D hole system at the surface of a wide band gap semiconductor. With a spin relaxation length that is experimentally accessible using existing nanofabrication techniques, this result suggests that hydrogen-terminated diamond has great potential for the study and application of spin transport phenomena.
Single-electron transistor coupled to a silicon nano-MOSFET
Publisher: SPIE
Date: 23-02-2005
DOI: 10.1117/12.583293
Radio-frequency reflectometry-A fast and sensitive measurement method for two-dimensional systems
Publisher: Elsevier BV
Date: 02-2010
Fabrication and characterization of ambipolar devices on an undoped AlGaAs/GaAs heterostructure
Publisher: AIP Publishing
Date: 30-01-2012
DOI: 10.1063/1.3673837
Abstract: We have fabricated AlGaAs/GaAs heterostructure devices in which the conduction channel can be populated with either electrons or holes simply by changing the polarity of a gate bias. The heterostructures are entirely undoped, and carriers are, instead, induced electrostatically. We use these devices to perform a direct comparison of the scattering mechanisms of two-dimensional electrons (μpeak = 4 × 106 cm2/Vs) and holes (μpeak = 0.8 × 106 cm2/Vs) in the same conduction channel with nominally identical disorder potentials. We find significant discrepancies between electron and hole scattering, with the hole mobility being considerably lower than expected from simple theory.
Manifestation of a non-Abelian Berry phase in a p-type semiconductor system
Publisher: American Physical Society (APS)
Date: 17-05-2016
Origin of gate hysteresis in p-type Si-doped AlGaAs/GaAs heterostructures
Publisher: American Physical Society (APS)
Date: 08-10-2012
Coherent electronic transfer in quantum dot systems using adiabatic passage
Publisher: American Physical Society (APS)
Date: 15-12-2004
Related Organisations
University Of Cambridge
Location: United Kingdom of Great Britain and Northern Ireland
Imperial College London
Location: United Kingdom of Great Britain and Northern Ireland
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