ORCID Profile
0000-0003-3124-4430
Current Organisations
Durban University of Technology
,
Brown University
,
Monash University
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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 | Functional Materials | Metals and Alloy Materials | Electronic and Magnetic Properties of Condensed Matter; Superconductivity | Electronic and magnetic properties of condensed matter; superconductivity | Condensed matter physics | Interdisciplinary Engineering not elsewhere classified | Electrochemistry | Materials Engineering not elsewhere classified | Nanotechnology not elsewhere classified | Functional materials | Condensed matter characterisation technique development | Nanomaterials | Nanotechnology | Materials Engineering | Degenerate Quantum Gases and Atom Optics | Condensed Matter Modelling and Density Functional Theory | Condensed Matter Characterisation Technique Development | Nanoelectronics
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Technology | Management of Greenhouse Gas Emissions from Information and Communication Services | Emerging Defence Technologies | Manufacturing not elsewhere classified | Basic Metal Products (incl. Smelting, Rolling, Drawing and Extruding) not elsewhere classified | Commercial Energy Conservation and Efficiency | Energy not elsewhere classified | Industrial Chemicals and Related Products not elsewhere classified | Structural Metal Products |
Related Links
Publications
Enhanced charge carrier mobility in two-dimensional high dielectric molybdenum oxide
Publisher: Wiley
Date: 23-10-2013
Abstract: We demonstrate that the energy bandgap of layered, high-dielectric α-MoO(3) can be reduced to values viable for the fabrication of 2D electronic devices. This is achieved through embedding Coulomb charges within the high dielectric media, advantageously limiting charge scattering. As a result, devices with α-MoO(3) of ∼11 nm thickness and carrier mobilities larger than 1100 cm(2) V(-1) s(-1) are obtained.
Localized Wannier function based tight-binding models for two-dimensional allotropes of bismuth
Publisher: IOP Publishing
Date: 06-2021
Abstract: With its monoelemental composition, various crystalline forms and an inherently strong spin–orbit coupling, bismuth has been regarded as an ideal prototype material to expand our understanding of topological electronic structures. In particular, two-dimensional bismuth thin films have attracted a growing interest due to potential applications in topological transistors and spintronics. This calls for an effective physical model to give an accurate interpretation of the novel topological phenomena shown by two-dimensional bismuth. However, the conventional semi-empirical approach of adapting bulk bismuth hoppings fails to capture the topological features of two-dimensional bismuth allotropes because the electronic band topology is heavily influenced by crystalline symmetries. Here we provide a new parameterization using localized Wannier functions derived from the Bloch states in first-principles calculations. We construct new tight-binding models for three types of two-dimensional bismuth allotropes: a Bi (111) bilayer, bismuthene and a Bi (110) bilayer. We demonstrate that our tight-binding models can successfully reproduce the electronic and topological features of these two-dimensional allotropes. Moreover, these tight-binding models can be used to explain the physical origin of the occurrence of novel band topology and the perturbation effects in these bismuth allotropes. In addition, these models can serve as a starting point for investigating the electron/spin transport and electromagnetic response in low-dimensional topological devices.
Wavelength‐Controlled Photocurrent Polarity Switching in BP‐MoS2 Heterostructure
Publisher: Wiley
Date: 20-03-2022
Abstract: Layered 2D van der Waals semiconductors and their heterostructures have been shown to exhibit positive photoconductance (PPC) in many studies. A few recent reports have demonstrated negative photoconductance (NPC) as well that can enable broadband photodetection besides multi‐level optoelectronic logic and memory. Controllable and reversible switching between PPC and NPC is a key requirement for these applications. This report demonstrates visible‐to‐near infrared wavelength‐driven NPC and PPC, along with reversible switching between the two, in an air stable, high mobility, broadband black phosphorus field effect transistor covered with a few layer MoS 2 flake. The crossover switching wavelength can be tuned by varying the MoS 2 bandgap through its flake thickness and the NPC and PPC photoresponsivities can be modulated using electrostatic gating as well as laser power. Recombination‐driven NPC and PPC, as supported by density functional theory calculations, allows for reversible switching. Further, gate voltage‐dependent negative persistent photoconductance is well‐suited for optosynaptic applications.
Hydrogen induced amorphisation around nanocracks in aluminium
Publisher: Elsevier BV
Date: 08-2016
A saccharide-based binder for efficient polysulfide regulations in Li-S batteries
Publisher: Springer Science and Business Media LLC
Date: 10-09-2021
DOI: 10.1038/S41467-021-25612-5
Abstract: The viability of lithium-sulfur batteries as an energy storage technology depends on unlocking long-term cycle stability. Most instability stems from the release and transport of polysulfides from the cathode, which causes mossy growth on the lithium anode, leading to continuous consumption of electrolyte. Therefore, development of a durable cathode with minimal polysulfide escape is critical. Here, we present a saccharide-based binder system that has a capacity for the regulation of polysulfides due to its reducing properties. Furthermore, the binder promotes the formation of viscoelastic filaments during casting which endows the sulfur cathode with a desirable web-like microstructure. Taken together this leads to 97% sulfur utilisation with a cycle life of 1000 cycles (9 months) and capacity retention (around 700 mAh g −1 after 1000 cycles). A pouch cell prototype with a specific energy of up to 206 Wh kg −1 is produced, demonstrating the promising potential for practical applications.
The bi-layered precipitate phase ζ in the Al-Ag alloy system
Publisher: Elsevier BV
Date: 06-2017
Reply to “Comment on ‘Atomistic Mechanisms of Mg Insertion Reactions in Group XIV Anodes for Mg-Ion Batteries’”
Publisher: American Chemical Society (ACS)
Date: 10-03-2020
Self-assembling surface stress domains far from equilibrium
Publisher: AIP Publishing
Date: 17-12-2007
DOI: 10.1063/1.2825568
Abstract: We have used real-time low-energy electron microscopy to observe the growth and shape evolutions of self-assembled stress domains on Si(111) surfaces. We find that elastic strain leads to dramatic transformations in the shapes of large domains that are not predicted by existing theoretical models. By comparing the experimental observations on the formation of the stress domains with dynamic growth simulations, we have developed a quantitative understanding of how a self-assembling system falls out of equilibrium. Our work shows the nonequilibrium shapes that a domain adopts during growth depending very strongly on the azimuthal dependence of its boundary energy.
Phase‐Control of Single‐Crystalline Inorganic Halide Perovskites via Molecular Coordination Engineering
Publisher: Wiley
Date: 22-12-2021
Abstract: The excellent optoelectronic properties and structural stability of inorganic cesium lead halide perovskites make them promising candidates for multiple types of optoelectronic devices. However, it remains a challenge to fabricate monocrystalline phase‐pure perovskite microstructures by facile low‐temperature solution‐based methods. Herein, a solution‐based method is demonstrated for controlling the crystallization of cesium halide perovskite microstructures. The structure of perovskite crystals is successfully tuned from non‐corner sharing Cs 4 PbBr 6 (0D) to corner‐sharing CsPbBr 3 (3D) to layered CsPb 2 Br 5 (2D) by controlling water (H 2 O) to dimethylsulfoxide (DMSO) ratios. Molecular dynamics simulations and thermodynamic analysis indicate that the relative stability of Pb 2+ and Br − ions in solution is the key factor in determining which crystals form at different H 2 O/DMSO ratios, with Cs + simply incorporated as needed. The phase‐pure 0D crystals exhibit a high photoluminescence quantum yield of 41%, whilst the 2D crystals have an onset of absorption at 350 nm. Furthermore, the as‐synthesized, highly uniform 3D perovskite single crystals are coupled with nanofabricated interdigitated electrodes to show excellent X‐ray detection, with a high sensitivity of 8000 μC Gy air −1 cm −2 obtained under a 0.5V external bias. This is comparable to many commercial X‐ray detectors (Si, α‐Se) and several times higher than other reported inorganic perovskite materials (CsPbBr 3 quantum dots, Cs 2 AgBiBr 6 ).
Giant piezoresistivity in a van der Waals material induced by intralayer atomic motions
Publisher: Research Square Platform LLC
Date: 18-07-2022
DOI: 10.21203/RS.3.RS-1859907/V1
Abstract: The presence of the van der Waals (vdW) gap in layered materials creates a wealth of intriguing phenomena different to their counterparts in conventional materials. For ex le, pressurization can generate a large anisotropic lattice shrinkage along the vdW stacking orientation and/or a significant interlayer sliding, and many of the exotic pressure-dependent properties derive from these mechanisms. Here we report a giant piezoresistivity in pressurized \\(\\beta \\text{’}\\)-In 2 Se 3 . Upon compression, a six-orders-of-magnitude drop of electrical resistivity is obtained below 1.2 GPa in \\(\\beta \\text{’}\\)-In 2 Se 3 flakes, yielding a giant piezoresistive gauge \\({\\pi }_{P}\\) of -5.33 GPa − 1 . Simultaneously, the s le undergoes a semiconductor-to-semimetal transition without a structural phase transition. Surprisingly, linear dichroism study and theoretical first principles modelling show that these phenomena arise not due to shrinkage or sliding at the vdW gap, but rather are dominated by the layer-dependent atomic motions inside the quintuple layer, mainly from the shifting of middle Se atoms to their high-symmetric location. Our work not only provides a prominent piezoresistive material but also points out the importance of intralayer atomic motions beyond vdW gap.
Aqueous electrochemistry of the magnesium surface: Thermodynamic and kinetic profiles
Publisher: Elsevier BV
Date: 02-2019
Substrate-induced magnetism in epitaxial graphene buffer layers
Publisher: IOP Publishing
Date: 17-06-2029
DOI: 10.1088/0957-4484/20/27/275705
Abstract: Magnetism in graphene is of fundamental as well as technological interest, with potential applications in molecular magnets and spintronic devices. While defects and/or adsorbates in freestanding graphene nanoribbons and graphene sheets have been shown to cause itinerant magnetism, controlling the density and distribution of defects and adsorbates is in general difficult. We show from first principles calculations that graphene buffer layers on SiC(0001) can also show intrinsic magnetism. The formation of graphene-substrate chemical bonds disrupts the graphene pi-bonds and causes localization of graphene states near the Fermi level. Exchange interactions between these states lead to itinerant magnetism in the graphene buffer layer. We demonstrate the occurrence of magnetism in graphene buffer layers on both bulk-terminated as well as more realistic adatom-terminated SiC(0001) surfaces. Our calculations show that adatom density has a profound effect on the spin distribution in the graphene buffer layer, thereby providing a means of engineering magnetism in epitaxial graphene.
Molecular Dipole-Driven Electronic Structure Modifications of DNA/RNA Nucleobases on Graphene
Publisher: American Chemical Society (ACS)
Date: 22-06-2017
DOI: 10.1021/ACS.JPCLETT.7B01283
Abstract: The emergence of graphene in recent years provides exciting avenues for achieving fast, reliable DNA/RNA sensing and sequencing. Here we explore the possibility of enhancing electronic fingerprints of nucleobases adsorbed on graphene by tuning the surface coverage and modifying molecular dipoles using first-principles calculations. We demonstrate that intermolecular interactions have a strong influence on the adsorption geometry and the electronic structure of the nucleobases, resulting in tilted configurations and a considerable modification of their electronic fingerprints in graphene. Our analysis reveals that the molecular dipole of the nucleobase molecules plays a dominant role in the electronic structure of graphene-nucleobase systems, inducing significant changes in the work functions and energy level alignments at the interface. These results highlight tunable control of the measured molecular signals in graphene by optimizing the surface contact between nucleobases and graphene. Our findings have important implications for identification and understanding of molecular fingerprints of DNA/RNA nucleobases in graphene-based sensing and sequencing methods.
Allotropes selection apropos of photocatalytic CO2 reduction from first principles studies
Publisher: Elsevier BV
Date: 09-2022
Microstructural evolution of strained heteroepitaxial multilayers
Publisher: AIP Publishing
Date: 28-04-2008
DOI: 10.1063/1.2906488
Abstract: A nonlinear model using the phase-field approach is developed to study microstructural evolution during the growth of strained heteroepitaxial multilayers. The strain from the buried layers is observed to influence the nucleation of islands in subsequently deposited strained layers. The patterns obtained during the evolution of multilayers are determined by the interplay of strain relaxation and deposition flux leading to formation of coordinated, stacked islands in the low flux regime and planar growth in the high flux regime, in agreement with the experimental observations.
Extracting unconventional spin texture in two dimensional topological crystalline insulator bismuthene via tuning bulk-edge interactions
Publisher: Elsevier BV
Date: 08-2023
Enhanced Photovoltaic Performance via a Bifunctional Additive in Tin-Based Perovskite Solar Cells
Publisher: American Chemical Society (ACS)
Date: 20-12-2021
Exploring graphene as a corrosion protection barrier
Publisher: Elsevier BV
Date: 03-2012
Compositional patterning in coherent and dislocated alloy nanocrystals
Publisher: Elsevier BV
Date: 09-2009
Corrosion mechanism and hydrogen evolution on Mg
Publisher: Elsevier BV
Date: 04-2015
Influence of electric field on SERS: Frequency effects, intensity changes, and susceptible bonds
Publisher: American Chemical Society (ACS)
Date: 12-2012
DOI: 10.1021/JA208893Q
Abstract: The fundamental mechanism proposed to explain surface-enhanced Raman scattering (SERS) relies on electromagnetic field enhancement at optical frequencies. In this work, we demonstrate the use of microfabricated, silver nanotextured electrode pairs to study, in situ, the influence of low frequency (5 mHz to 1 kHz) oscillating electric fields on the SERS spectra of thiophenol. This applied electric field is shown to affect SERS peak intensities and influence specific vibrational modes of the analyte. The applied electric field perturbs the polar analyte, thereby altering the scattering cross section. Peaks related to the sulfurous bond which binds the molecule to the silver nanotexture exhibit strong and distinguishable responses to the applied field, due to varying bending and stretching mechanics. Density functional theory simulations are used to qualitatively verify the experimental observations. Our experimental and simulation results demonstrate that the SERS spectral changes relate to electric field induced molecular reorientation, with dependence on applied field strength and frequency. This demonstration creates new opportunities for external dynamic tuning and multivariate control of SERS measurements.
Enhanced lithium adsorption and diffusion on silicene nanoribbons
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3RA43326A
First principles many-body calculations of electronic structure and optical properties of SiC nanoribbons
Publisher: IOP Publishing
Date: 08-02-2016
DOI: 10.1088/0022-3727/49/10/105306
Abstract: A first principles many-body approach is employed to calculate the band structure and optical response of nanometer-sized ribbons of SiC. Many-body effects are incorporated using the GW approximation, and excitonic effects are included using the Bethe–Salpeter equation. Both unpassivated and hydrogen-passivated armchair SiC nanoribbons are studied. As a consequence of low dimensionality, large quasiparticle corrections are seen to the Kohn–Sham energy gaps. In both cases quasiparticle band gaps are increased by up to 2 eV, as compared to their Kohn–Sham energy values. Inclusion of electron–hole interactions modifies the absorption spectra significantly, giving rise to strongly bound excitonic peaks in these systems. The results suggest that hydrogen passivated armchair SiC nanoribbons have the potential to be used in optoelectronic devices operating in the UV-Vis region of the spectrum. We also compute the formation energies of these nanoribbons as a function of their widths, and conclude that hydrogen-saturated ribbons will be much more stable as compared to bare ones.
Resolving the FCC/HCP interfaces of the γ' (Ag2Al) precipitate phase in aluminium
Publisher: Elsevier BV
Date: 08-2019
Dirac-point photocurrents due to the photothermoelectric effect in non-uniform graphene devices
Publisher: Springer Science and Business Media LLC
Date: 17-02-2020
Enhanced quantum confinement due to nonuniform composition in alloy quantum dots
Publisher: IOP Publishing
Date: 03-02-2010
DOI: 10.1088/0957-4484/21/9/095401
Abstract: Strain and nanoscale variations in composition can significantly alter the electronic and optical properties of self-assembled alloy quantum systems. Using a combination of finite element and first-principles methods, we have developed an efficient and accurate technique to study the influence of strain and composition on the quantum confinement behavior in alloy quantum dots. Interestingly, we find that a nonuniform distribution of alloy components can lead to an enhanced confinement potential that allows a large quantum dot to behave electronically in a manner similar to a much smaller dot. The approach presented here provides a general means to quantitatively predict the influence of strain and composition variations on the performance characteristics of various small-scale alloy systems.
Edge stresses of non-stoichiometric edges in two-dimensional crystals
Publisher: AIP Publishing
Date: 18-06-2012
DOI: 10.1063/1.4729940
Abstract: The elastic properties of edges are among the most fundamental properties of finite two-dimensional (2D) crystals. Using a combination of the first-principles density functional theory calculations and a continuum elasticity model, we present an efficient technique to determine the edge stresses of non-stoichiometric orientations in multicomponent 2D crystals. Using BN and MoS2 as prototypical ex les of 2D binary monolayers with threefold in-plane symmetry, we unambiguously compute unique edge stresses of commonly observed non-stoichiometric edges. Our results show that the edge stresses for these structurally distinct orientations can differ significantly from the average values that have been typically reported to date.
Probing the dynamic structural changes of DNA using ultrafast laser pulse in graphene‐based optofluidic device
Publisher: Wiley
Date: 28-04-2020
DOI: 10.1002/INF2.12114
Atomistic insights into the adsorption and stimuli-responsive behavior of poly(N-isopropylacrylamide)–graphene hybrid systems
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CP04191A
Abstract: First fully atomistic study on PNIPAM/G-GO hybrid systems, unravelling their distinct adsorption and stimuli-responsive behaviors.
Tunable electronic properties of partially edge-hydrogenated armchair boron–nitrogen–carbon nanoribbons
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7CP08234G
Abstract: We employ a first-principles calculations based density-functional-theory (DFT) approach to study the electronic properties of partially and fully edge-hydrogenated armchair boron–nitrogen–carbon (BNC) nanoribbons (ABNCNRs), with widths between 0.85 nm to 2.3 nm.
Aqueous Electrochemical Activity of the Mg Surface: The Role of Group 14 and 15 Microalloying Elements
Publisher: The Electrochemical Society
Date: 2017
DOI: 10.1149/2.0071714JES
Postcombustion CO2 capture in functionalized porous coordination networks
Publisher: American Chemical Society (ACS)
Date: 13-12-2013
DOI: 10.1021/JP409361J
Hydrogen Bond Networks in Graphene Oxide Composite Paper: Structure and Mechanical Properties
Publisher: American Chemical Society (ACS)
Date: 09-04-2010
DOI: 10.1021/NN901934U
Abstract: A multilayered composite structure formed by a random stacking of graphene oxide (GO) platelets is an attractive candidate for novel applications in nanoelectromechanical systems and paper-like composites. We employ molecular dynamics simulations with reactive force fields to elucidate the structural and mechanical properties of GO paper-like materials. We find that the large-scale properties of these composites are controlled by hydrogen bond networks that involve functional groups on in idual GO platelets and water molecules within the interlayer cavities. Water content controls both the extent and collective strength of these interlayer hydrogen bond networks, thereby affecting the interlayer spacing and elastic moduli of the composite. Additionally, the chemical composition of the in idual GO platelets also plays a critical role in establishing the mechanical properties of the composite--a higher density of functional groups leads to increased hydrogen bonding and a corresponding increase in stiffness. Our studies suggest the possibility of tuning the properties of GO composites by altering the density of functional groups on in idual platelets, the water content, and possibly the functional groups participating in hydrogen bonding with interlayer water molecules.
Improved structural and optical properties of Cu2ZnSnS4 thin films via optimized potential in single bath electrodeposition
Publisher: Elsevier BV
Date: 08-2014
Electrochemical control of photoluminescence in two-dimensional MoS 2 nanoflakes
Publisher: American Chemical Society (ACS)
Date: 24-10-2013
DOI: 10.1021/NN4041987
Abstract: Two-dimensional (2D) transition metal dichalcogenide semiconductors offer unique electronic and optical properties, which are significantly different from their bulk counterparts. It is known that the electronic structure of 2D MoS2, which is the most popular member of the family, depends on the number of layers. Its electronic structure alters dramatically at near atomically thin morphologies, producing strong photoluminescence (PL). Developing processes for controlling the 2D MoS2 PL is essential to efficiently harness many of its optical capabilities. So far, it has been shown that this PL can be electrically or mechanically gated. Here, we introduce an electrochemical approach to actively control the PL of liquid-phase-exfoliated 2D MoS2 nanoflakes by manipulating the amount of intercalated ions including Li(+), Na(+), and K(+) into and out of the 2D crystal structure. These ions are selected as they are crucial components in many bioprocesses. We show that this controlled intercalation allows for large PL modulations. The introduced electrochemically controlled PL will find significant applications in future chemical and bio-optical sensors as well as optical modulators/switches.
On the prismatic precipitate plates in Mg-Ca-In alloys
Publisher: Elsevier BV
Date: 05-2015
CO2adsorption and separation in covalent organic frameworks with interlayer slipping
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CE01647F
Abstract: In layered COFs, slipping results in non-monotonous variation in CO 2 adsorption and higher uptakes were found near a slipping distance of 10 Å.
Manifestation of Strongly Correlated Electrons in a 2D Kagome Metal–Organic Framework
Publisher: Wiley
Date: 12-09-2021
Abstract: 2D and layered electronic materials characterized by a kagome lattice, whose valence band structure includes two Dirac bands and one flat band, can host a wide range of tunable topological and strongly correlated electronic phases. While strong electron correlations have been observed in inorganic kagome crystals, they remain elusive in organic systems, which benefit from versatile synthesis protocols via molecular self‐assembly and metal‐ligand coordination. Here, direct experimental evidence of local magnetic moments resulting from strong electron–electron Coulomb interactions in a 2D metal–organic framework (MOF) is reported. The latter consists of di‐cyano‐anthracene (DCA) molecules arranged in a kagome structure via coordination with copper (Cu) atoms on a silver surface [Ag(111)]. Temperature‐dependent scanning tunneling spectroscopy reveals magnetic moments spatially confined to DCA and Cu sites of the MOF, and Kondo screened by the Ag(111) conduction electrons. By density functional theory and mean‐field Hubbard modeling, it is shown that these magnetic moments are the direct consequence of strong Coulomb interactions between electrons within the kagome MOF. The findings pave the way for nanoelectronics and spintronics technologies based on controllable correlated electron phases in 2D organic materials.
Cation/Anion Substitution in Cu2ZnSnS4 for Improved Photovoltaic Performance
Publisher: Springer Science and Business Media LLC
Date: 17-10-2016
DOI: 10.1038/SREP35369
Abstract: Cations and anions are replaced with Fe, Mn, and Se in CZTS in order to control the formations of the secondary phase, the band gap, and the micro structure of Cu 2 ZnSnS 4 . We demonstrate a simplified synthesis strategy for a range of quaternary chalcogenide nanoparticles such as Cu 2 ZnSnS 4 (CZTS), Cu 2 FeSnS 4 (CFTS), Cu 2 MnSnS 4 (CMTS), Cu 2 ZnSnSe 4 (CZTSe), and Cu 2 ZnSn(S 0.5 Se 0.5 ) 4 (CZTSSe) by thermolysis of metal chloride precursors using long chain amine molecules. It is observed that the crystal structure, band gap and micro structure of the CZTS thin films are affected by the substitution of anion/cations. Moreover, secondary phases are not observed and grain sizes are enhanced significantly with selenium doping (grain size ~1 μm). The earth-abundant Cu 2 MSnS 4 /Se 4 (M = Zn, Mn and Fe) nanoparticles have band gaps in the range of 1.04–1.51 eV with high optical-absorption coefficients (~10 4 cm −1 ) in the visible region. The power conversion efficiency of a CZTS solar cell is enhanced significantly, from 0.4% to 7.4% with selenium doping, within an active area of 1.1 ± 0.1 cm 2 . The observed changes in the device performance parameters might be ascribed to the variation of optical band gap and microstructure of the thin films. The performance of the device is at par with sputtered fabricated films, at similar scales.
Using optical spectroscopy to probe the impact of atomic disorder on the Heusler alloy
C
Publisher: American Physical Society (APS)
Date: 14-09-2023
Near‐Infrared and Visible‐Range Optoelectronics in 2D Hybrid Perovskite/Transition Metal Dichalcogenide Heterostructures
Publisher: Wiley
Date: 30-03-2022
Abstract: The application of ultrathin 2D perovskites in near‐infrared and visible‐range optoelectronics is limited owing to their inherent wide bandgaps, large excitonic binding energies, and low optical absorption at higher wavelengths. Here, it is shown that by tailoring interfacial band alignments via conjugation with low‐dimensional materials like monolayer transition metal dichalcogenides (TMD), the functionalities of 2D perovskites can be extended to erse, visible‐range photophysical applications. Based on the choice of in idual constituents in the 2D perovskite/TMD heterostructures, first principles calculations demonstrate widely tunable type‐II bandgaps, carrier effective masses, and band offsets to enable an effective separation of photogenerated excitons for enhanced photodetection and photovoltaic applications. In addition, the possibilities of achieving a type‐I band alignment for recombination‐based light emitters as well as a type‐III configuration for tunneling devices are shown. Further, the effect of strain on the electronic properties of the heterostructures are evaluated to show a significant strain tolerance, making them prospective candidates in flexible photosensors.
Stress enhanced calcium kinetics in a neuron
Publisher: Springer Science and Business Media LLC
Date: 23-08-2017
DOI: 10.1007/S10237-017-0952-0
Abstract: Accurate modeling of the mechanobiological response of a Traumatic Brain Injury is beneficial toward its effective clinical examination, treatment and prevention. Here, we present a stress history-dependent non-spatial kinetic model to predict the microscale phenomena of secondary insults due to accumulation of excess calcium ions (Ca[Formula: see text]) induced by the macroscale primary injuries. The model is able to capture the experimentally observed increase and subsequent partial recovery of intracellular Ca[Formula: see text] concentration in response to various types of mechanical impulses. We further establish the accuracy of the model by comparing our predictions with key experimental observations.
Efficient atomic-scale kinetics through a complex heterophase interface
Publisher: American Physical Society (APS)
Date: 25-07-2013
Asymmetric gel polymer electrolyte with high lithium ion conductivity for dendrite-free lithium metal batteries
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA01883J
Abstract: An asymmetric gel polymer electrolyte is designed for regulating ions and suppressing Li dendrite growth in high-performance Li metal batteries.
Protease activated receptor-1 mediated dual kinase receptor transactivation stimulates the expression of glycosaminoglycan synthesizing genes
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.CELLSIG.2015.11.003
Abstract: G protein-coupled receptors (GPCR) are one of the most important targets for therapeutics due to their abundance and ersity. The G protein-coupled receptor for thrombin can transactivate protein tyrosine kinase receptors (PTKR) and we have recently established that it can also transactivate serine/threonine kinase receptors (S/TKR). A comprehensive knowledge of the signalling pathways that GPCR transactivation elicits is necessary to fully understand the implications of both GPCR activation and the impact of target drugs. Here, we demonstrate that thrombin elicits dual transactivation-dependent signalling pathways to stimulate mRNA expression of glycosaminoglycan synthesizing enzymes chondroitin 4-O-sulfotransferase 1 and chondroitin sulfate synthase 1. The PTKR mediated response involves matrix metalloproteinases and the phosphorylation of the MAP kinase Erk. The S/TKR mediated response differs markedly and involves the phosphorylation of Smad2 carboxy terminal serine residues and does not involve matrix metalloproteinases. This work shows that all of the thrombin mediated signalling to glycosaminoglycan synthesizing enzyme gene expression occurs via transactivation-dependent pathways and does not involve transactivation-independent signalling. These findings highlight the complexity of thrombin-mediated transactivation signalling and the broader implications of GPCR targeted therapeutics.
Computational design of multilayer frameworks to achieve DOE target for on-board methane delivery
Publisher: Elsevier BV
Date: 11-2019
Influence of the Cu2ZnSnS4 nanoparticles size on solar cell performance
Publisher: Elsevier BV
Date: 2019
Methane Adsorption and Separation in Slipped and Functionalized Covalent Organic Frameworks
Publisher: American Chemical Society (ACS)
Date: 20-03-2018
Electric Field Control of Molecular Charge State in a Single-Component 2D Organic Nanoarray
Publisher: American Chemical Society (ACS)
Date: 04-10-2019
Abstract: Quantum dots (QD) with electric-field-controlled charge state are promising for electronics applications,
Band engineering of Ni1−xMgxO alloys for photocathodes of high efficiency dye-sensitized solar cells
Publisher: AIP Publishing
Date: 15-12-2012
DOI: 10.1063/1.4769210
Abstract: Density functional theory calculations were carried out for Ni1−xMgxO alloys using both GGA+U method and hybrid exchange-correlation functional HSE06. We find that the band gap of Ni1−xMgxO is a nonlinear function of MgO concentration with a strong bowing behavior at high Mg content. Band edge alignment is determined using heterojunction superlattice models. The valence-band-maximum of Ni1−xMgxO is shown to be tunable within a range of 0.90 eV. By comparing with the highest-occupied-molecular-orbital levels of some of the most widely used dye molecules, we propose that Ni1−xMgxO is a promising alternate to replace NiO photocathode in dye-sensitized solar cells with an enhanced open-circuit voltage and transparency of cathode films.
Predicting the early stages of solid-state precipitation in Al-rich Al-Pt alloys
Publisher: Elsevier BV
Date: 08-2023
Designing Optoelectronic Properties by On-Surface Synthesis: Formation and Electronic Structure of an Iron–Terpyridine Macromolecular Complex
Publisher: American Chemical Society (ACS)
Date: 18-06-2018
Abstract: Supramolecular chemistry protocols applied on surfaces offer compelling avenues for atomic-scale control over organic-inorganic interface structures. In this approach, adsorbate-surface interactions and two-dimensional confinement can lead to morphologies and properties that differ dramatically from those achieved via conventional synthetic approaches. Here, we describe the bottom-up, on-surface synthesis of one-dimensional coordination nanostructures based on an iron (Fe)-terpyridine (tpy) interaction borrowed from functional metal-organic complexes used in photovoltaic and catalytic applications. Thermally activated diffusion of sequentially deposited ligands and metal atoms and intraligand conformational changes lead to Fe-tpy coordination and formation of these nanochains. We used low-temperature scanning tunneling microscopy and density functional theory to elucidate the atomic-scale morphology of the system, suggesting a linear tri-Fe linkage between facing, coplanar tpy groups. Scanning tunneling spectroscopy reveals the highest occupied orbitals, with dominant contributions from states located at the Fe node, and ligand states that mostly contribute to the lowest unoccupied orbitals. This electronic structure yields potential for hosting photoinduced metal-to-ligand charge transfer in the visible/near-infrared. The formation of this unusual tpy/tri-Fe/tpy coordination motif has not been observed for wet chemistry synthetic methods and is mediated by the bottom-up on-surface approach used here, offering pathways to engineer the optoelectronic properties and reactivity of metal-organic nanostructures.
Porous aromatic frameworks impregnated with lithiated fullerenes for natural gas purification
Publisher: American Chemical Society (ACS)
Date: 16-04-2015
Erratum: Tunable plasmon resonances in two-dimensional molybdenum oxide nanoflakes (Advanced Materials (2014) 26 (3931-3937))
Publisher: Wiley
Date: 08-2014
Chemical switching of low-loss phonon polaritons in α-MoO3 by hydrogen intercalation
Publisher: Springer Science and Business Media LLC
Date: 27-05-2020
DOI: 10.1038/S41467-020-16459-3
Abstract: Phonon polaritons (PhPs) have attracted significant interest in the nano-optics communities because of their nanoscale confinement and long lifetimes. Although PhP modification by changing the local dielectric environment has been reported, controlled manipulation of PhPs by direct modification of the polaritonic material itself has remained elusive. Here, chemical switching of PhPs in α-MoO 3 is achieved by engineering the α-MoO 3 crystal through hydrogen intercalation. The intercalation process is non-volatile and recoverable, allowing reversible switching of PhPs while maintaining the long lifetimes. Precise control of the intercalation parameters enables analysis of the intermediate states, in which the needle-like hydrogenated nanostructures functioning as in-plane antennas effectively reflect and launch PhPs and form well-aligned cavities. We further achieve spatially controlled switching of PhPs in selective regions, leading to in-plane heterostructures with various geometries. The intercalation strategy introduced here opens a relatively non-destructive avenue connecting infrared nanophotonics, reconfigurable flat metasurfaces and van der Waals crystals.
Thermal transport in lattice-constrained 2D hybrid graphene heterostructures
Publisher: IOP Publishing
Date: 03-10-2013
DOI: 10.1088/0953-8984/25/44/445007
Abstract: The thermal transport properties of hybrid graphene/h-BN heterostructures are investigated using atomistic simulations. While the thermal conductivity is observed to be significantly limited perpendicular to the graphene/h-BN interface, it is tunable via a composition parallel to the interface. In particular we show that the thermal transport parallel to the interface can be understood by viewing the hybrid system as a series of in idual embedded graphene nanoribbons (GNRs) constrained by neighboring h-BN. A mechanistic model is proposed to relate the thermal conductivities of the embedded and free-standing GNRs through a linear function of the composition. The model predictions are demonstrated to be in good agreement with the simulation results.
Detection of Halomethanes Using Cesium Lead Halide Perovskite Nanocrystals
Publisher: American Chemical Society (ACS)
Date: 13-01-2021
Correlation-induced magnetism in substrate-supported 2D metal-organic frameworks
Publisher: Springer Science and Business Media LLC
Date: 08-11-2022
DOI: 10.1038/S41524-022-00918-0
Abstract: Two-dimensional (2D) metal-organic frameworks (MOFs) with a kagome lattice can exhibit strong electron-electron interactions, which can lead to tunable quantum phases including many exotic magnetic phases. While technological developments of 2D MOFs typically take advantage of substrates for growth, support, and electrical contacts, investigations often ignore substrates and their dramatic influence on electronic properties. Here, we show how substrates alter the correlated magnetic phases in kagome MOFs using systematic density functional theory and mean-field Hubbard calculations. We demonstrate that MOF-substrate coupling, MOF-substrate charge transfer, strain, and external electric fields are key variables, activating and deactivating magnetic phases in these materials. While we consider the ex le of kagome-arranged 9,10-dicyanoanthracene molecules coordinated with copper atoms, our findings should generalise to any 2D kagome material. This work offers useful predictions for tunable interaction-induced magnetism in surface-supported 2D (metal-)organic materials, opening the door to solid-state electronic and spintronic technologies based on such systems.
Atomistic Mechanisms of Mg Insertion Reactions in Group XIV Anodes for Mg-Ion Batteries
Publisher: American Chemical Society (ACS)
Date: 11-12-2019
Abstract: Magnesium (Mg) metal has been widely explored as an anode material for Mg-ion batteries (MIBs) owing to its large specific capacity and dendrite-free operation. However, critical challenges, such as the formation of passivation layers during battery operation and anode-electrolyte-cathode incompatibilities, limit the practical application of Mg-metal anodes for MIBs. Motivated by the promise of group XIV elements (namely, Si, Ge, and Sn) as anodes for lithium- and sodium-ion batteries, here, we conduct systematic first-principles calculations to explore the thermodynamics and kinetics of group XIV anodes for MIBs and to identify the atomistic mechanisms of the electrochemical insertion reactions of Mg ions. We confirm the formation of amorphous Mg
The formation mechanism of Janus nanostructures in one-pot reactions: The case of Ag-Ag8 GeS6
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6TA00398B
Abstract: Using Ag–Ag 8 GeS 6 as a model system, a novel strategy for the formation of Ag-based Janus nanostructures is presented.
Shape dynamics in anisotropically strained two-dimensional self-assembling systems
Publisher: AIP Publishing
Date: 15-03-2008
DOI: 10.1063/1.2890153
Abstract: We analyze the evolution of equilibrium and growth shapes of anisotropically strained two-dimensional self-assembled structures using a dynamic growth model. As ex les of such structures, we study the shapes of nanowires grown heteroepitaxially on cubic (001) surfaces and monolayer islands or stress domains grown homoepitaxially on Si(001) surface. In the former case, the anisotropy in the mismatch strain in the two principal directions is large, while in the latter case, the principal components of the strain are equal in magnitude and opposite in sign. In the case of nanowires, we find that the slow kinetics of growth limits the formation of wirelike shapes with constant widths as predicted by equilibrium models. In particular, the aspect ratios of nanowires during growth are considerably smaller than the equilibrium aspect ratios. For monolayer islands on Si(001), we show that the anisotropy in strain gives rise to a novel fourfold symmetry in their equilibrium shapes. This strain-induced symmetry, coupled with the kinetics of growth, is shown to result in rich shape dynamics of monolayer islands on Si(001) as seen in recent experiments.
Crossover from 2D Ferromagnetic Insulator to Wide Band Gap Quantum Anomalous Hall Insulator in Ultrathin MnBi2Te4
Publisher: American Chemical Society (ACS)
Date: 13-08-2021
Abstract: Intrinsic magnetic topological insulators offer low disorder and large magnetic band gaps for robust magnetic topological phases operating at higher temperatures. By controlling the layer thickness, emergent phenomena such as the quantum anomalous Hall (QAH) effect and axion insulator phases have been realized. These observations occur at temperatures significantly lower than the Néel temperature of bulk MnBi
CO2 Adsorption in Azobenzene Functionalized Stimuli Responsive Metal-Organic Frameworks
Publisher: American Chemical Society (ACS)
Date: 21-12-0004
Transforming solid-state precipitates via excess vacancies
Publisher: Springer Science and Business Media LLC
Date: 06-03-2020
DOI: 10.1038/S41467-020-15087-1
Abstract: Many phase transformations associated with solid-state precipitation look structurally simple, yet, inexplicably, take place with great difficulty. A classic case of difficult phase transformations is the nucleation of strengthening precipitates in high-strength lightweight aluminium alloys. Here, using a combination of atomic-scale imaging, simulations and classical nucleation theory calculations, we investigate the nucleation of the strengthening phase θ′ onto a template structure in the aluminium-copper alloy system. We show that this transformation can be promoted in s les exhibiting at least one nanoscale dimension, with extremely high nucleation rates for the strengthening phase as well as for an unexpected phase. This template-directed solid-state nucleation pathway is enabled by the large influx of surface vacancies that results from heating a nanoscale solid. Template-directed nucleation is replicated in a bulk alloy as well as under electron irradiation, implying that this difficult transformation can be facilitated under the general condition of sustained excess vacancy concentrations.
Elastic softening of alloy negative electrodes for Na-ion batteries
Publisher: Elsevier BV
Date: 03-2013
Large Magnetic Gap in a Designer Ferromagnet–Topological Insulator–Ferromagnet Heterostructure
Publisher: Wiley
Date: 31-03-2022
Abstract: Combining magnetism and nontrivial band topology gives rise to quantum anomalous Hall (QAH) insulators and exotic quantum phases such as the QAH effect where current flows without dissipation along quantized edge states. Inducing magnetic order in topological insulators via proximity to a magnetic material offers a promising pathway toward achieving the QAH effect at a high temperature for lossless transport applications. One promising architecture involves a sandwich structure comprising two single‐septuple layers (1SL) of MnBi 2 Te 4 (a 2D ferromagnetic insulator) with ultrathin few quintuple layer (QL) Bi 2 Te 3 in the middle, and it is predicted to yield a robust QAH insulator phase with a large bandgap greater than 50 meV. Here, the growth of a 1SL MnBi 2 Te 4 /4QL Bi 2 Te 3 /1SL MnBi 2 Te 4 heterostructure via molecular beam epitaxy is demonstrated and the electronic structure probed using angle‐resolved photoelectron spectroscopy. Strong hexagonally warped massive Dirac fermions and a bandgap of 75 ± 15 meV are observed. The magnetic origin of the gap is confirmed by the observation of the exchange‐Rashba effect, as well as the vanishing bandgap above the Curie temperature, in agreement with density functional theory calculations. These findings provide insights into magnetic proximity effects in topological insulators and reveal a promising platform for realizing the QAH effect at elevated temperatures.
Composition maps in self-assembled alloy quantum dots
Publisher: American Physical Society (APS)
Date: 14-03-2008
Energetics and kinetics of li intercalation in irradiated graphene scaffolds
Publisher: American Chemical Society (ACS)
Date: 13-12-2013
DOI: 10.1021/AM403685W
Abstract: In the present study, we investigate the irradiation-defects hybridized graphene scaffold as one potential building material for the anode of Li-ion batteries. Designating the Wigner V2(2) defect as a representative, we illustrate the interplay of Li atoms with the irradiation defects in graphene scaffolds. We examine the adsorption energetics and diffusion kinetics of Li in the vicinity of a Wigner V2(2) defect using density functional theory calculations. The equilibrium Li adsorption sites at the defect are identified and shown to be energetically preferable to the adsorption sites on pristine (bilayer) graphene. Meanwhile, the minimum energy paths and corresponding energy barriers for Li migration at the defect are determined and computed. We find that, while the defect is shown to exhibit certain trapping effects on Li motions on the graphene surface, it appears to facilitate the interlayer Li diffusion and enhance the charge capacity within its vicinity, because of the reduced interlayer spacing and characteristic symmetry associated with the defect. Our results provide critical assessment for the application of irradiated graphene scaffolds in Li-ion batteries.
Freestanding n-Doped Graphene via Intercalation of Calcium and Magnesium into the Buffer Layer–SiC(0001) Interface
Publisher: American Chemical Society (ACS)
Date: 15-07-2020
Mechanisms of void shrinkage in aluminium
Publisher: International Union of Crystallography (IUCr)
Date: 10-08-2016
DOI: 10.1107/S1600576716010657
Abstract: Voids can significantly affect the performance of materials and a key question is how voids form and evolve. Voids also provide a rare opportunity to study the fundamental interplay between surface crystallography and atomic diffusion at the nanoscale. In the present work, the shrinkage of voids in aluminium from 20 to 1 nm in diameter through in situ annealing is imaged in a transmission electron microscope. It is found that voids first shrink anisotropically from a non-equilibrium to an equilibrium shape and then shrink while maintaining their equilibrium shape until they collapse. It is revealed that this process maximizes the reduction in total surface energy per vacancy emitted. It is also observed that shrinkage is quantized, taking place one atomic layer and one void facet at a time. By taking the quantization and electron irradiation into account, the measured void shrinkage rates can be modelled satisfactorily for voids down to 5 nm using bulk diffusion kinetics. Continuous electron irradiation accelerates the shrinkage kinetics significantly however, it does not affect the energetics, which control void shape.
Atomistic Insights into the Reformation of CH4 with CO2 on Metal-Free gC3N4: Unraveling the Reaction Mechanisms Using First-Principles DFT Calculations
Publisher: American Chemical Society (ACS)
Date: 13-10-2021
The enhanced theta-prime (θ′) precipitation in an Al-Cu alloy with trace Au additions
Publisher: Elsevier BV
Date: 02-2017
Bonding Charge Density and Ultimate Strength of Monolayer Transition Metal Dichalcogenides
Publisher: American Chemical Society (ACS)
Date: 18-07-2013
DOI: 10.1021/JP403986V
Derivative procedure for BEM based computation of change in natural frequency with crack size
Publisher: Springer Science and Business Media LLC
Date: 2002
From Half-Metal to Semiconductor: Electron-Correlation Effects in Zigzag SiC Nanoribbons From First Principles
Publisher: American Physical Society (APS)
Date: 09-06-2017
Electrochemical Stability of Magnesium Surfaces in an Aqueous Environment
Publisher: American Chemical Society (ACS)
Date: 18-11-2016
Metastability in 2D self-assembling systems
Publisher: American Physical Society (APS)
Date: 12-10-2007
High capacity group-15 alloy anodes for Na-ion batteries: Electrochemical and mechanical insights
Publisher: Elsevier BV
Date: 07-2015
Discriminative separation of gases by a molecular trapdoor mechanism in chabazite zeolites
Publisher: American Chemical Society (ACS)
Date: 13-11-2012
DOI: 10.1021/JA309274Y
Abstract: Separation of molecules based on molecular size in zeolites with appropriate pore aperture dimensions has given rise to the definition of "molecular sieves" and has been the basis for a variety of separation applications. We show here that for a class of chabazite zeolites, what appears to be "molecular sieving" based on dimension is actually separation based on a difference in ability of a guest molecule to induce temporary and reversible cation deviation from the center of pore apertures, allowing for exclusive admission of certain molecules. This new mechanism of discrimination permits "size-inverse" separation: we illustrate the case of admission of a larger molecule (CO) in preference to a smaller molecule (N(2)). Through a combination of experimental and computational approaches, we have uncovered the underlying mechanism and show that it is similar to a "molecular trapdoor". Our materials show the highest selectivity of CO(2) over CH(4) reported to date with important application to natural gas purification.
Plasmon resonances of highly doped two-dimensional MoS2
Publisher: American Chemical Society (ACS)
Date: 08-01-2015
DOI: 10.1021/NL503563G
Abstract: The exhibition of plasmon resonances in two-dimensional (2D) semiconductor compounds is desirable for many applications. Here, by electrochemically intercalating lithium into 2D molybdenum disulfide (MoS2) nanoflakes, plasmon resonances in the visible and near UV wavelength ranges are achieved. These plasmon resonances are controlled by the high doping level of the nanoflakes after the intercalation, producing two distinct resonance peak areas based on the crystal arrangements. The system is also benchmarked for biosensing using bovine serum albumin. This work provides a foundation for developing future 2D MoS2 based biological and optical units.
Non-uniform composition distribution in alloy quantum structures
Publisher: IEEE
Date: 12-2010
Tunable Plasmon Resonances in Two-Dimensional Molybdenum Oxide Nanoflakes
Publisher: Wiley
Date: 26-03-2014
Berry curvature origin of the thickness-dependent anomalous Hall effect in a ferromagnetic Weyl semimetal
Publisher: Springer Science and Business Media LLC
Date: 19-02-2021
DOI: 10.1038/S41535-021-00315-8
Abstract: Magnetic Weyl semimetals with spontaneously broken time-reversal symmetry exhibit a large intrinsic anomalous Hall effect originating from the Berry curvature. To employ this large Hall current for room temperature topo-spintronics applications, it is necessary to fabricate these materials as thin or ultrathin films. Here, we experimentally demonstrate that Weyl semimetal Co 2 MnGa thin films (20–50 nm) show a large anomalous Hall angle ~11.4% at low temperature and ~9.7% at room temperature, which can be ascribed to the non-trivial topology of the band structure with large intrinsic Berry curvature. However, the anomalous Hall angle decreases significantly with thicknesses below 20 nm, which band structure calculations confirm is due to the reduction of the majority spin contribution to the Berry curvature. Our results suggest that Co 2 MnGa is an excellent material to realize room temperature topo-spintronics applications however, the significant thickness dependence of the Berry curvature has important implications for thin-film device design.
The Edge Stresses and Phase Transitions for Magnetic BN Zigzag Nanoribbons
Publisher: Springer Science and Business Media LLC
Date: 10-08-2017
DOI: 10.1038/S41598-017-08364-5
Abstract: The edge states are of particular importance to understand fundamental properties of finite two-dimensional (2D) crystals. Based on first-principles calculations, we investigated on the bare zigzag boron nitride nanoribbons (zzBNNRs) with different spin-polarized states well localized at and extended along their edges. Our calculations examined the edge stress, which is sensitively dependent on the magnetic edge states, for either B-terminated edge or N-terminated edge. Moreover, we revealed that different magnetic configurations lead to a rich spectrum of electronic behaviors at edges. Using an uniaxial tensile strain, we proposed the magnetic phase transitions and thereby obtained the metallic to half-metallic (or reverse) phase transitions at edges. It suggests zzBNNR as a promising candidate for potential applications of non-metal spintronic devices.
Electronic Band Structure of In-Plane Ferroelectric van der Waals β′-In2Se3
Publisher: American Chemical Society (ACS)
Date: 15-01-2020
Molecular mechanisms of thermal instability in hybrid perovskite light absorbers for photovoltaic solar cells
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA05356B
Abstract: This work explores the molecular-level mechanisms of thermal instability in pristine and defective crystals of the prototypical hybrid perovskite MAPbI 3 .
Enhancing kinetic and electrochemical performance of layered MoS2 cathodes with interlayer expansion for Mg-ion batteries
Publisher: Elsevier BV
Date: 09-2022
Proposal for a Negative Capacitance Topological Quantum Field-Effect Transistor
Publisher: IEEE
Date: 11-12-2021
The bulk and interfacial structures of the η (Al2 Au) precipitate phase
Publisher: Elsevier BV
Date: 02-2016
Selective control of surface spin current in topological pyrite-type OsX2 (X = Se, Te) crystals
Publisher: Springer Science and Business Media LLC
Date: 21-08-2019
DOI: 10.1038/S41535-019-0186-8
Abstract: Topological materials host robust surface states that could form the basis for future electronic devices. As such states have spins that are locked to the momentum, they are of particular interest for spintronic applications. Understanding spin textures of the surface states of topologically nontrivial materials, and being able to manipulate their polarization, is therefore essential if they are to be utilized in future technologies. Here we use first-principles calculations to show that pyrite-type crystals OsX 2 (X = Se, Te) are a class of topological materials that can host surface states with spin polarization that can be either in-plane or out-of-plane. We show that the formation of low-energy states with symmetry-protected energy- and direction-dependent spin textures on the (001) surface of these materials is a consequence of a transformation from a topologically trivial to nontrivial state, induced by spin orbit interactions. The unconventional spin textures of these surface states feature an in-plane to out-of-plane spin polarization transition in the momentum space protected by local symmetries. Moreover, the surface spin direction and magnitude can be selectively filtered in specific energy ranges. Our demonstration of a new class of topological materials with controllable spin textures provides a platform for experimentalists to detect and exploit unconventional surface spin textures in future spin-based nanoelectronic devices.
Vacancy-tuned precipitation pathways in Al-1.7 Cu-0.025In-0.025Sb (at.%) alloy
Publisher: Elsevier BV
Date: 12-2017
Surface Charge Transfer Induced Ferromagnetism in Nanostructured ZnO/Al
Publisher: American Chemical Society (ACS)
Date: 10-04-2012
DOI: 10.1021/JP211523F
The effect of absorbed hydrogen on the dissolution of steel
Publisher: Elsevier BV
Date: 12-2016
Molecularly Controlled Quantum Well Width Distribution and Optoelectronic Properties in Quasi-2D Perovskite Light-Emitting Diodes
Publisher: American Chemical Society (ACS)
Date: 03-05-2022
DOI: 10.1021/ACS.JPCLETT.2C00360
Abstract: Owing to their excellent optoelectronic properties, quasi-2D perovskites with self-assembled multiple quantum well (MQW) structures have shown great potential in light-emitting diode (LED) applications. Understanding the correlation between the bulky cation, quantum well assembly, and optoelectronic properties of a quasi-2D perovskite is important. Here, we demonstrate that the dipole moment of the bulky cation can be one of the fundamental factors that controls the distribution and crystallinity of different quantum wells. We find that the bulky cation with a moderate dipole moment leads to moderately distributed well-width MQWs, resulting in a superior device efficiency due to the simultaneous achievement of favorable optical and electronic properties. The peak external quantum efficiency and the maximum luminance of the ch ion device are 10.8% and 19082 cd m
Spontaneous formation and growth of a new polytype on SiC(0001)
Publisher: American Physical Society (APS)
Date: 14-12-2009
Tunable Hybridization between Electronic States of Graphene and Physisorbed Hexacene
Publisher: American Chemical Society (ACS)
Date: 06-08-2015
Ab initio characterization of layered MoS2 as anode for sodium-ion batteries
Publisher: Elsevier BV
Date: 12-2014
Enzymatic and non-enzymatic electrochemical glucose sensor based on carbon nano-onions
Publisher: Elsevier BV
Date: 06-2018
Polarity-Tunable Photocurrent through Band Alignment Engineering in a High-Speed WSe2/SnSe2 Diode with Large Negative Responsivity
Publisher: American Chemical Society (ACS)
Date: 21-02-2022
Abstract: Excellent light-matter interaction and a wide range of thickness-tunable bandgaps in layered vdW materials coupled by the facile fabrication of heterostructures have enabled several avenues for optoelectronic applications. Realization of high photoresponsivity at fast switching speeds is a critical challenge for 2D optoelectronics to enable high-performance photodetection for optical communication. Moving away from conventional type-II heterostructure pn junctions towards a WSe
Giant piezoresistivity in a van der Waals material induced by intralayer atomic motions
Publisher: Springer Science and Business Media LLC
Date: 18-03-2023
DOI: 10.1038/S41467-023-37239-9
Abstract: The presence of the van der Waals gap in layered materials creates a wealth of intriguing phenomena different to their counterparts in conventional materials. For ex le, pressurization can generate a large anisotropic lattice shrinkage along the stacking orientation and/or a significant interlayer sliding, and many of the exotic pressure-dependent properties derive from these mechanisms. Here we report a giant piezoresistivity in pressurized β ′-In 2 Se 3 . Upon compression, a six-orders-of-magnitude drop of electrical resistivity is obtained below 1.2 GPa in β′ -In 2 Se 3 flakes, yielding a giant piezoresistive gauge π p of −5.33 GPa −1 . Simultaneously, the s le undergoes a semiconductor-to-semimetal transition without a structural phase transition. Surprisingly, linear dichroism study and theoretical first principles modelling show that these phenomena arise not due to shrinkage or sliding at the van der Waals gap, but rather are dominated by the layer-dependent atomic motions inside the quintuple layer, mainly from the shifting of middle Se atoms to their high-symmetric location. The atomic motions link to both the band structure modulation and the in-plane ferroelectric dipoles. Our work not only provides a prominent piezoresistive material but also points out the importance of intralayer atomic motions beyond van der Waals gap.
Ion Agglomeration and Transport in MgCl2 -Based Electrolytes for Rechargeable Magnesium Batteries
Publisher: American Chemical Society (ACS)
Date: 02-12-2019
DOI: 10.1021/ACS.JPCLETT.9B03023
Abstract: Magnesium halide salts are an exciting prospect as stable and high-performance electrolytes for rechargeable Mg batteries (RMBs). By nature of their complex equilibria, these salts exist in solution as a variety of electroactive species (EAS) in equilibrium with counterions such as AlCl
Stability and formation mechanisms of carbonyl- and hydroxyl-decorated holes in graphene oxide
Publisher: American Chemical Society (ACS)
Date: 25-06-2010
DOI: 10.1021/JP908801C
Comparison of fatigue crack growth stress ratio effects under simple variable amplitude loading using fractographic and strain measurements
Publisher: Elsevier BV
Date: 07-2018
Correction to “Atomistic Mechanisms of Mg Insertion Reactions in Group XIV Anodes for Mg-Ion Batteries”
Publisher: American Chemical Society (ACS)
Date: 25-11-2019
Postgraduate Supervision - Future foci for the knowledge society
Publisher: SUN PRESS
Date: 22-11-2016
Ordered intracrystalline pores in planar molybdenum oxide for enhanced alkaline hydrogen evolution
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8TA08330D
Abstract: Planner hexagonal molybdenum oxide as an emerging electrocatalyst for the hydrogen evolution reaction (HER) in alkaline media.
Derivative procedure for BEM based computation of change in natural frequency with crack size
Publisher: Springer Science and Business Media LLC
Date: 2002
Strong Depletion in Hybrid Perovskite p–n Junctions Induced by Local Electronic Doping
Publisher: Wiley
Date: 03-2018
Abstract: A semiconductor p-n junction typically has a doping-induced carrier depletion region, where the doping level positively correlates with the built-in potential and negatively correlates with the depletion layer width. In conventional bulk and atomically thin junctions, this correlation challenges the synergy of the internal field and its spatial extent in carrier generation/transport. Organic-inorganic hybrid perovskites, a class of crystalline ionic semiconductors, are promising alternatives because of their direct badgap, long diffusion length, and large dielectric constant. Here, strong depletion in a lateral p-n junction induced by local electronic doping at the surface of in idual CH
Coherent backscattering in the topological Hall effect
Publisher: IOP Publishing
Date: 25-04-2023
Abstract: The mutual interplay between electron transport and magnetism has attracted considerable attention in recent years, primarily motivated by strategies to manipulate magnetic degrees of freedom electrically, such as spin–orbit torques and domain wall motion. Within this field the topological Hall effect, which originates from scalar spin chirality, is an ex le of inter-band quantum coherence induced by real-space inhomogeneous magnetic textures, and its magnitude depends on the winding number and chiral spin features that establish the total topological charge of the system. Remarkably, in the two decades since its discovery, there has been no research on the quantum correction to the topological Hall effect. Here we will show that, unlike the ordinary Hall effect, the inhomogeneous magnetization arising from the spin texture will give additional scattering terms in the kinetic equation, which result in a quantum correction to the topological Hall resistivity. We focus on two-dimensional systems, where weak localization is strongest, and determine the complicated gradient corrections to the Cooperon and kinetic equation. Whereas the weak localization correction to the topological Hall effect is not large in currently known materials, we show that it is experimentally observable in dilute magnetic semiconductors. Our theoretical results will stimulate experiments on the topological Hall effect and fill the theoretical knowledge gap on weak localization corrections to transverse transport.
Magnesium-intercalated graphene on SiC: Highly n-doped air-stable bilayer graphene at extreme displacement fields
Publisher: Elsevier BV
Date: 03-2021
Enhancement of the intrinsic light harvesting capacity of Cs2AgBiBr6double perovskiteviamodification with sulphide
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9TA10422D
Abstract: Light harvesting capacity of caesium silver bismuth bromide double perovskite need to be enhanced to render this non-toxic and thermodynamically stable material suitable for photovoltaic applications, for ex le as a top layer in tandem solar cells.
Near-Direct Bandgap WSe2/ReS2 Type-II pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics
Publisher: American Chemical Society (ACS)
Date: 20-02-2020
A first-principles study of electronic properties of H and F-terminated zigzag BNC nanoribbons
Publisher: Author(s)
Date: 2016
DOI: 10.1063/1.4946627
Unraveling the roles of single transition metal atom anchored on equivalent stoichiometry graphitic carbon nitride (gC6N6) for carbon dioxide reduction: a density functional theo
Publisher: IOP Publishing
Date: 09-12-2022
Abstract: CO 2 photoreduction into hydrocarbon fuels is a promising strategy in closing the carbon cycle to realize a sustainable energy economy. Among the many photocatalysts that have been developed thus far, porous graphitic carbon nitride (gC 6 N 6 ) has emerged as a potential photocatalyst candidate in view of its unique optoelectronic properties, metal-free nature and two-dimensional versatile structure that can be easily modified. In this work, the enhancement of equivalent stoichiometry carbon nitride (gC 6 N 6 ) through single transition metal atom modification was systematically studied from first principles density functional theory calculations. The formation energy calculations revealed that incorporating single Co, Cu, Ni or Pd atom into gC 6 N 6 is energetically favorable, with the exception of Pt. The computed density of states plot indicates that a greater degree of hybridization of the transition metal atom d-orbitals with the p-orbitals of O atom from CO 2 will lead to stronger adsorption interaction. The optical absorption spectra show that Cu, Pd, and Pt promotes greater light absorption by extending the optical absorption to the NIR region. The presence of additional dopant states near the Fermi surface was found to have affected the optical absorption. The band structures of the Co,Cu,Pd,Pt@gC 6 N 6 show bandgap narrowing due to the shifting of conduction band edge closer to the Fermi level. Contrastingly, Ni@gC 6 N 6 exhibits bandgap narrowing through the shifting of the valence band edge to the Fermi level. The band edge positions suggest that anchoring gC 6 N 6 with single Co, Cu, Ni, Pd and Pt atom dopants possesses the capability to reduce CO 2 into C1 products. Among all the transition metals studied, Pd@gC 6 N 6 and Cu@gC 6 N 6 are identified as the most promising single-atom photocatalysts for CO 2 reduction due to their energetically favorable formation energy, stable CO 2 adsorption configuration, narrow bandgap, low charge carrier recombination, extended light absorption range and suitable band edge positions.
Stress-enhanced pattern formation on surfaces during low energy ion bombardment
Publisher: IOP Publishing
Date: 12-05-2009
DOI: 10.1088/0953-8984/21/22/224021
Abstract: Ion-induced surface patterns (sputter ripples) are observed to grow more rapidly than predicted by current models, suggesting that additional sources of roughening may be involved. Using a linear stability analysis, we consider the contribution of ion-induced stress in the near surface region to the formation rate of ripples. This leads to a simple model that combines the effects of stress-induced roughening with the curvature-dependent erosion model of Bradley and Harper. The enhanced growth rate observed on Cu surfaces appears to be consistent with the magnitude of stress measured from wafer curvature measurements.
Composite Polymer Electrolyte for Highly Cyclable Room-Temperature Solid-State Magnesium Batteries
Publisher: American Chemical Society (ACS)
Date: 22-10-2019
Gigantic Anisotropy of Self-Induced Spin-Orbit Torque in Weyl Ferromagnet Co2MnGa
Publisher: American Chemical Society (ACS)
Date: 21-07-2023
Spatial calcium kinetics after a traumatic brain injury
Publisher: Springer Science and Business Media LLC
Date: 27-03-2021
DOI: 10.1007/S10237-021-01453-5
Abstract: Accurate modelling of intracellular calcium ion ([Formula: see text]) concentration evolution is valuable as it is known to rapidly increase during a Traumatic Brain Injury. In the work presented here, our older non-spatial model dealing with the effect of mechanical stress upon the [Formula: see text] transportation in a neuron is spatialized by considering the brain tissue as a solid continuum with the [Formula: see text] activity occurring at every material point. Starting with one-dimensional representation, the brain tissue geometry is progressively made realistic and under the action of pressure or kinematic impulses, the effect of dimensionality and material behaviour on the correlation between the stress and concomitant [Formula: see text] concentration is investigated. The spatial calcium kinetics model faithfully captures the experimental observations concerning the [Formula: see text] concentration, load rate, magnitude and duration and most importantly shows that the critical location for primary injury may not be the most important location as far as secondary injury is concerned.
Non-equivalent zigzag edge stresses for 2D binary compound honeycomb nanoribbons
Publisher: IEEE
Date: 12-2012
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End Date: 09-2027
Amount: $4,379,165.00
Funder: Australian Research Council
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