ORCID Profile
0000-0001-6434-2569
Current Organisations
Lunds Universitet
,
Peking University
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Publisher: AIP Publishing
Date: 23-04-2007
DOI: 10.1063/1.2732829
Abstract: The authors demonstrate operation of a charge readout scheme for quantum dots in a semiconductor nanowire using a quantum point contact defined in a GaAs∕AlGaAs two-dimensional electron gas beneath the nanowire. The quantum dots were fabricated by epitaxial growth of InP barriers along a n-type InAs nanowire. Applying negative voltages to two split-gate electrodes aligned to the nanowire induces a quantum point contact in the two-dimensional electron gas such that charging of quantum dots in the nanowire modulates the quantum point contact transmission, thus resulting in the desired detector response.
Publisher: Springer Science and Business Media LLC
Date: 22-04-2016
DOI: 10.1038/SREP24822
Abstract: Hybrid InSb nanowire-superconductor devices are promising for investigating Majorana modes and topological quantum computation in solid-state devices. An experimental realisation of ballistic, phase-coherent superconductor-nanowire hybrid devices is a necessary step towards engineering topological superconducting electronics. Here, we report on a low-temperature transport study of Josephson junction devices fabricated from InSb nanowires grown by molecular-beam epitaxy and provide a clear evidence for phase-coherent, ballistic charge transport through the nanowires in the junctions. We demonstrate that our devices show gate-tunable proximity-induced supercurrent and clear signatures of multiple Andreev reflections in the differential conductance, indicating phase-coherent transport within the junctions. We also observe periodic modulations of the critical current that can be associated with the Fabry-Pérot interference in the nanowires in the ballistic transport regime. Our work shows that the InSb nanowires grown by molecular-beam epitaxy are of excellent material quality and hybrid superconducting devices made from these nanowires are highly desirable for investigation of the novel physics in topological states of matter and for applications in topological quantum electronics.
Publisher: American Chemical Society (ACS)
Date: 19-08-2009
DOI: 10.1021/NL901333A
Abstract: We report on magnetotransport measurements on InSb nanowire quantum dots. The measurements show that the quantum levels of the InSb quantum dots have giant g factors, with absolute values up to approximately 70, the largest value ever reported for semiconductor quantum dots. We also observe that the values of these g factors are quantum level dependent and can differ strongly between different quantum levels. The presence of giant g factors indicates that considerable contributions from the orbital motion of electrons are preserved in the measured InSb nanowire quantum dots, while the level-to-level fluctuations arise from spin-orbit interaction. We have deduced a value of Delta(SO) = 280 mueV for the strength of spin-orbit interaction from an avoided level crossing between the ground state and first excited state of an InSb nanowire quantum dot with a fixed number of electrons.
Publisher: American Physical Society (APS)
Date: 06-06-2013
Publisher: IOP Publishing
Date: 02-2017
Publisher: American Physical Society (APS)
Date: 12-01-2010
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2011
Publisher: American Physical Society (APS)
Date: 20-01-2017
Publisher: Springer Science and Business Media LLC
Date: 12-2014
DOI: 10.1038/SREP07261
Publisher: American Chemical Society (ACS)
Date: 28-11-2012
DOI: 10.1021/NL303758W
Abstract: Semiconductor InSb nanowires are expected to provide an excellent material platform for the study of Majorana fermions in solid state systems. Here, we report on the realization of a Nb-InSb nanowire-Nb hybrid quantum device and the observation of a zero-bias conductance peak structure in the device. An InSb nanowire quantum dot is formed in the device between the two Nb contacts. Due to the proximity effect, the InSb nanowire segments covered by the superconductor Nb contacts turn to superconductors with a superconducting energy gap Δ(InSb) ∼ 0.25 meV. A tunable critical supercurrent is observed in the device in high back gate voltage regions in which the Fermi level in the InSb nanowire is located above the tunneling barriers of the quantum dot and the device is open to conduction. When a perpendicular magnetic field is applied to the devices, the critical supercurrent is seen to decrease as the magnetic field increases. However, at sufficiently low back gate voltages, the device shows the quasi-particle Coulomb blockade characteristics and the supercurrent is strongly suppressed even at zero magnetic field. This transport characteristic changes when a perpendicular magnetic field stronger than a critical value, at which the Zeeman energy in the InSb nanowire is E(z) ∼ Δ(InSb), is applied to the device. In this case, the transport measurements show a conductance peak at the zero bias voltage and the entire InSb nanowire in the device behaves as in a topological superconductor phase. We also show that this zero-bias conductance peak structure can persist over a large range of applied magnetic fields and could be interpreted as a transport signature of Majorana fermions in the InSb nanowire.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5NR04273A
Abstract: Single electron transport is demonstrated in high-quality MBE-grown InSb nanowire single quantum dots with a dot length up to ∼700 nm.
Publisher: American Chemical Society (ACS)
Date: 21-03-2008
DOI: 10.1021/NL073193Y
Abstract: We investigate electrical properties of self-assembled branched InAs nanowires. The branched nanowires are catalytically grown using chemical beam epitaxy, and three-terminal nanoelectronic devices are fabricated from the branched nanowires using electron-beam lithography. We demonstrate that, in difference from conventional macroscopic junctions, the fabricated self-assembled nanowire junction devices exhibit tunable nonlinear electrical characteristics and a signature of ballistic electron transport. As an ex le of applications, we demonstrate that the self-assembled three-terminal nanowire junctions can be used to implement the functions of frequency mixing, multiplication, and phase-difference detection of input electrical signals at room temperature. Our results suggest a wide range of potential applications of branched semiconductor nanostructures in nanoelectronics.
Publisher: American Physical Society (APS)
Date: 27-10-2008
Publisher: American Chemical Society (ACS)
Date: 13-12-2011
DOI: 10.1021/NL203380W
Abstract: Epitaxially grown, high quality semiconductor InSb nanowires are emerging material systems for the development of high performance nanoelectronics and quantum information processing and communication devices and for the studies of new physical phenomena in solid state systems. Here, we report on measurements of a superconductor-normal conductor-superconductor junction device fabricated from an InSb nanowire with aluminum-based superconducting contacts. The measurements show a proximity-induced supercurrent flowing through the InSb nanowire segment with a critical current tunable by a gate in the current bias configuration and multiple Andreev reflection characteristics in the voltage bias configuration. The temperature dependence and the magnetic field dependence of the critical current and the multiple Andreev reflection characteristics of the junction are also studied. Furthermore, we extract the excess current from the measurements and study its temperature and magnetic field dependences. The successful observation of the superconductivity in the InSb nanowire-based Josephson junction device indicates that InSb nanowires provide an excellent material system for creating and observing novel physical phenomena such as Majorana fermions in solid-state systems.
Publisher: American Physical Society (APS)
Date: 04-05-2010
No related grants have been discovered for Hongqi Xu.