A5027499535- 2D Materials and Applications
- Perovskite Materials and Applications
- Chalcogenide Semiconductor Thin Films
- Graphene research and applications
- Solid-state spectroscopy and crystallography
- Multiferroics and related materials
- Electronic and Structural Properties of Oxides
- Boron and Carbon Nanomaterials Research
- Machine Learning in Materials Science
- Quantum Dots Synthesis And Properties
- MXene and MAX Phase Materials
- Arctic and Antarctic ice dynamics
- Advanced Condensed Matter Physics
- Software System Performance and Reliability
- Mobile Agent-Based Network Management
- Galaxies: Formation, Evolution, Phenomena
- Model-Driven Software Engineering Techniques
- Cryospheric studies and observations
- Nanowire Synthesis and Applications
- Stellar, planetary, and galactic studies
- Magnetic and transport properties of perovskites and related materials
- Advanced Semiconductor Detectors and Materials
- Meteorological Phenomena and Simulations
- Molecular Junctions and Nanostructures
- Topological Materials and Phenomena
University of Warwick
2021-2025
Rutherford Appleton Laboratory
2025
Henry Royce Institute
2016-2021
University of Manchester
2016-2021
University of Oxford
2016
We apply a multiscale modeling approach to study lattice reconstruction in marginally twisted bilayers of transition metal dichalcogenides (TMD). For this, we develop DFT-parametrized interpolation formulae for interlayer adhesion energies MoSe$_2$, WSe$_2$, MoS$_2$, and WS$_2$, combine those with elasticity theory, analyze the bilayer relaxation into mesoscale domain structures. Paying particular attention inversion asymmetry TMD monolayers, show that 3R 2H stacking domains, separated by...
We present a tight-binding (TB) model and $\mathbf{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{p}$ theory for electrons in monolayer few-layer InSe. The is constructed from basis of all $s$ $p$ valence orbitals on both indium selenium atoms, with parameters obtained fitting to independently computed density functional (DFT) band structures mono- bilayer For the conduction edges InSe, which appear be vicinity $\mathrm{\ensuremath{\Gamma}}$ point, we calculate absorption coefficient...
Two-dimensional semiconductors - atomic layers of materials with covalent intra-layer bonding and weak (van der Waals or quadrupole) coupling between the are a new class great potential for optoelectronic applications. Among those, special position is now being taken by post-transition metal chalcogenides (PTMC), InSe GaSe. It has recently been found that band gap in 2D crystals more than doubles monolayer compared to thick multilayer crystals, while high mobility conduction electrons...
Two-dimensional monochalcogenides (MX) have been identified as a unique and promising class of layered materials in recent years. The valence band single-layer MX, predicted by theory, is inverted into bow-shaped (often referred to an sombrero) relatively flat dispersion, which expected give rise strongly correlated effects. inversion leads indirect gap, consistent with photoluminescence (PL) experiments, but PL provides no direct evidence the band. Here we demonstrate for hexagonal MX...
Twistronic van der Waals heterostrutures offer exciting opportunities for engineering optoelectronic properties of nanomaterials. Here, we use multiscale modeling to study trapping charge carriers and excitons by ferroelectric polarisation piezoelectric charges domain structures in twistronic WX$_2$/MoX$_2$ bilayers (X=S,Se). For almost aligned 2H-type bilayers, find that holes electrons are trapped the opposite -- WMo XX (tungsten over molybdenum {\it versus} overlaying chalcogens) corners...
Control over the electronic spectrum at low energy is heart of functioning modern advanced electronics: high electron mobility transistors, semiconductor and Capasso terahertz lasers, many others. Most those devices rely on meticulous engineering size quantization electrons in quantum wells. This avenue, however, hasn't been explored case 2D materials. Here we transfer this concept onto van der Waals heterostructures which utilize few-layers films InSe as The precise control subbands their...
Lattice reconstruction in twisted transition-metal dichalcogenide (TMD) bilayers gives rise to piezo- and ferroelectric moir\'e potentials for electrons holes, as well a modulation of the hybridisation across bilayer. Here, we develop hybrid $\mathbf{k}\cdot \mathbf{p}$ tight-binding models describe holes relevant valleys TMD homobilayers with parallel (P) anti-parallel (AP) orientations monolayer unit cells. We apply these superlattice effects WSe${}_2$ bilayers, conjunction microscopic...
Abstract The melting of submerged faces marine‐terminating glaciers is a key contributor to the glacial mass budget via direct thermodynamic ablation and impact on calving. This study considers behavior turbulent plumes buoyant meltwater in stratified ocean, generated by either near‐vertical calving or sloping ice shelves. We build insight applying plume model describe locally planar region face linearly regime where subglacial discharge insignificant. rise until becoming neutrally buoyant,...
We show that spin-orbit coupling (SOC) in InSe enables the optical transition across principal band gap to couple with in-plane polarized light. This transition, enabled by ${p}_{x,y}\ensuremath{\leftrightarrow}{p}_{z}$ hybridization due intra-atomic SOC both In and Se, can be viewed as a between two dominantly $s$- ${p}_{z}$-orbital based bands, accompanied an electron spin-flip. Having parametrized $\mathbf{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{p}$ theory using...
The relaxation of atomic positions to their optimal structural arrangement is crucial for understanding the emergence new physical behavior in long scale superstructures twisted bilayers two-dimensional materials. amount deviation from a rigid moiré structure will depend on elastic properties constituent monolayers which, bilayer, more flexible are, lower energy required deform layers maximize areas with an energetically interlayer atoms. We investigate this reconstruction highly InSe....
We propose atomic films of $n$-doped $\ensuremath{\gamma}$-InSe as a platform for intersubband optics in the infrared and far-infrared range, coupled to out-of-plane polarized light. Depending on film thickness (number layers) amount $n$-doping InSe film, these transitions span from $\ensuremath{\sim}0.7$ eV bilayer $\ensuremath{\sim}0.05$ 15-layer InSe. use hybrid $\mathbf{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{p}$ theory tight-binding model, fully parametrized using...
Abstract In two-dimensional heterostructures, crystalline atomic layers with differing lattice parameters can stack directly one on another. The resultant close proximity of lattices periodicity lead to new phenomena. For umklapp processes, this opens the possibility for interlayer scattering, where interactions are mediated by transfer momenta or from in neighbouring layer. Using angle-resolved photoemission spectroscopy study a graphene InSe heterostructure, we present evidence that...
We use dispersion-corrected density functional theory to determine the relative energies of competing polytypes bulk layered hexagonal post transition metal chalcogenides search for most stable structures these potentially technologically important semiconductors. show that there is some degree consensus among exchange-correlation functionals regarding energetic orderings polytypes, but we find each material are multiple stacking orders with less than 1 meV per monolayer unit cell, implying...
We demonstrate that spin-orbit coupling (SOC) strength for electrons near the conduction band edge in few-layer $\ensuremath{\gamma}$-InSe films can be tuned over a wide range. This tunability is result of competition between film-thickness-dependent intrinsic and electric-field-induced SOC, potentially, allowing electrically switchable spintronic devices. Using hybrid $\mathbf{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{p}$ tight-binding model, fully parametrized with help density...
In van der Waals heterostructures, the relative alignment of bands between layers, and resulting band hybridisation, are key factors in determining a range electronic properties. This work examines these effects for heterostructures transition metal dichalcogenides (TMDs) hexagonal boron nitride (hBN), an ubiquitous combination given role hBN as encapsulating material. By comparing results density functional calculations with experimental angle-resolved photoemission spectroscopy (ARPES)...
We investigate polarization memory effects in single-crystal CuFeO2, which has a magnetically-induced ferroelectric phase at low temperatures and applied B fields between 7.5 13 T. Following electrical poling of the phase, we find that nonpolar collinear antiferromagnetic ground state = 0 T retains strong magnitude direction, such upon re-entering net comparable to initial is recovered absence external bias. This effect very robust: pulsed-magnetic-field measurements, several pulses into...
The low-symmetry and anistropic lattice of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mn>1</a:mn><a:msup><a:mrow><a:mi mathvariant="normal">T</a:mi></a:mrow><a:mo>′</a:mo></a:msup><a:mspace width="4pt"/><a:msub><a:mi>WTe</a:mi><a:mn>2</a:mn></a:msub></a:mrow></a:math> is responsible for the existence parallel one-dimensional channels in moiré patterns twisted bilayers. This gives opportunity to explore physics a different nature that widely observed bilayers materials...
We perform a $\mathbf{k \cdot p}$ theory analysis of the spectra lowest energy and excited states excitons in few-layer atomically thin films InSe taking into account in-plane electric polarizability film influence encapsulation environment. For thinner films, lowest-energy state exciton is weakly indirect momentum space, with its dispersion showing minima at layer-number-dependent wave number, due to an inverted edge relatively flat topmost valence band branch spectrum we compute activation...
Abstract In bilayers of two-dimensional semiconductors with stacking arrangements which lack inversion symmetry charge transfer between the layers due to layer-asymmetric interband hybridisation can generate a potential difference layers. We analyse transition metal dichalcogenides (TMDs)—in particular, $$\hbox {WSe}_2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mtext>WSe</mml:mtext> <mml:mn>2</mml:mn> </mml:msub> </mml:math> —for we find substantial...
Twistronic assembly of 2D materials employs the twist angle between adjacent layers as a tuning parameter for designing electronic and optical properties van der Waals heterostructures. Here, we study how interlayer hybridization, weak ferroelectric charge transfer layers, piezoelectric response to deformations set valence conduction band edges across moir{é} supercell in twistronic homobilayers MoS$_2$, MoSe$_2$, WS$_2$ WSe$_2$. We show that, due lack inversion symmetry monolayer crystals,...
The relaxation of atomic positions to their optimal structural arrangement is crucial for understanding the emergence new physical behavior in long scale superstructures twisted bilayers two-dimensional materials. amount deviation from a rigid moir\'e structure will depend on elastic properties constituent monolayers which bilayer - more flexible are, lower energy required deform layers maximize areas with an energetically interlayer atoms. We investigate this reconstruction highly InSe....
The low symmetry and anistropic lattice of 1T$'$ WTe$_2$ is responsible for the existence parallel one-dimensional channels in moir\'e patterns twisted bilayers. This gives opportunity to explore physics a different nature that widely observed bilayers materials with hexagonal symmetries. Here, we combine plane-wave linear-scaling density functional theory calculations describe electronic properties bilayer WTe$_2$. For small change parameters constituent monolayers, find substantial...