A5001159769- 2D Materials and Applications
- Advanced Thermoelectric Materials and Devices
- MXene and MAX Phase Materials
- Thermal properties of materials
- Rare-earth and actinide compounds
- Magnetic Properties of Alloys
- Chalcogenide Semiconductor Thin Films
- Magnetic and transport properties of perovskites and related materials
- Graphene research and applications
- Boron and Carbon Nanomaterials Research
- Perovskite Materials and Applications
- Machine Learning in Materials Science
- Thermal Expansion and Ionic Conductivity
- Semiconductor materials and interfaces
- Advanced Condensed Matter Physics
- Nanowire Synthesis and Applications
- Heusler alloys: electronic and magnetic properties
- Nonlocal and gradient elasticity in micro/nano structures
- Topological Materials and Phenomena
- Surface and Thin Film Phenomena
- Crystallization and Solubility Studies
- Advanced Physical and Chemical Molecular Interactions
- Molecular Junctions and Nanostructures
- Inorganic Chemistry and Materials
- Optical properties and cooling technologies in crystalline materials
University of Antwerp
2020-2025
Oak Ridge National Laboratory
2017-2023
Kathmandu College of Management
2023
Indian Institute of Science Bangalore
2013-2020
Controlling the band gap by tuning lattice structure through pressure engineering is a relatively new route for tailoring optoelectronic properties of two-dimensional (2D) materials. Here, we investigate electronic and vibrational dynamics distorted monolayer 1T-MoS2 (1T′) 2H-MoS2 via diamond anvil cell (DAC) density functional theory (DFT) calculations. The direct optical increases 11.7% from 1.85 to 2.08 eV, which highest reported 2D transition metal dichalcogenide (TMD) material. DFT...
The sensitive dependence of the electronic and thermoelectric properties MoS2 on applied strain opens up a variety applications in emerging area straintronics. Using first-principles-based density functional theory calculations, we show that band gap few layers can be tuned by applying normal compressive (NC) strain, biaxial (BC) tensile (BT) strain. A reversible semiconductor-to-metal transition (S-M transition) is observed under all three types In case NC threshold at which S-M occurs...
Because of their weak interlayer bonding, van der Waals (vdW) solids are very sensitive to external stimuli such as strain. Experimental studies strain tuning thermal properties in vdW have not yet been reported. Under ∼9% cross-plane compressive created by hydrostatic pressure a diamond anvil cell, we observed an increase conductivity bulk MoS_{2} from 3.5 about 25 W m^{-1} K^{-1}, measured with picosecond transient thermoreflectance technique. First-principles calculations and coherent...
We investigate the electronic and thermal transport properties of bulk MX2 compounds (M = Zr, Hf X S, Se) by first-principles calculations semi-classical Boltzmann theory. The band structure shows confinement heavy light bands along out plane in-plane directions, respectively. This results in high electrical conductivity (σ) large thermopower leading to a power factor (S(2)σ) for moderate n-type doping. phonon dispersion demonstrates low frequency flat acoustical modes, which group...
We compare vibrational properties and phonon thermal conductivities (κ) of monolayer InSe, GaSe, GaS systems using density functional theory Peierls–Boltzmann transport methods. In going from InSe to GaSe GaS, system mass decreases giving both increasing acoustic velocities decreasing scattering these heat-carrying modes with optic phonons, ultimately . This behavior is demonstrated by correlating the phase space limited fundamental conservation conditions mode rates dispersions for each...
Phosphorene, a two-dimensional (2D) analog of black phosphorous, has been subject immense interest recently, due to its high carrier mobilities and tunable bandgap.So far, tunability predicted be obtained with very compressive/tensile in-plane strains, vertical electric field, which are difficult achieve experimentally.Here, we show using density functional theory based calculations the possibility tuning electronic properties by applying normal compressive strain in bilayer phosphorene.A...
Abstract Two-dimensional (2D) materials offer unique opportunities in engineering the ultrafast spatiotemporal response of composite nanomechanical structures. In this work, we report on high frequency, quality factor ( Q ) 2D acoustic cavities operating 50–600 GHz frequency f range with × up to 1 10 14 . Monolayer steps and material interfaces expand cavity functionality, as demonstrated by building adjacent that are isolated or strongly-coupled, well a comb generator MoS 2 /h-BN systems....
The magnetism in ${\mathrm{Mn}}_{3}{\mathrm{Si}}_{2}{\mathrm{Te}}_{6}$ has been investigated using thermodynamic measurements, first-principles calculations, neutron diffraction, and diffuse scattering on single crystals. These data confirm that is a ferrimagnet below ${T}_{\mathrm{C}}$ $\ensuremath{\approx}78$ K. anisotropic, with magnetization diffraction demonstrating the moments lie within basal plane of trigonal structure. saturation...
A unique way of achieving controllable, pressure-induced charge transfer doping in the graphene/MoS2 heterostructure is proposed. The causes an upward shift Dirac point with respect to Fermi level at a rate 15.7 meV GPa−1 as function applied hydrostatic pressure, leading heavy p-type graphene. was confirmed by I2D/IG measurements. As service our authors and readers, this journal provides supporting information supplied authors. Such materials are peer reviewed may be re-organized for online...
Single crystals of AlFe$_{2}$B$_{2}$ have been grown using the self flux growth method and then measured structural properties, temperature field dependent magnetization, electrical resistivity at ambient as well high pressure. The Curie is determined to be $274$~K. saturation magnetization effective moment for paramagnetic Fe-ion indicate itinerant nature magnetism with a Rhode-Wohlfarth ratio $ \frac{M_{C}}{M_{sat}}\approx 1.14$. Temperature measurements under hydrostatic pressure shows...
By combining first principles density functional theory and electronic as well lattice Boltzmann transport calculations, we unravel the excellent thermoelectric properties of Zintl phase compounds ACd2Sb2 (where, A = Ca, Ba, Sr). The calculated structures these show charge carrier pockets heavy light bands near band edge, which lead to a large power factor. Furthermore, report Grüneisen parameters low phonon group velocity indicating essential strong anharmonicity in compounds, resulted...
Achieving large thermoelectric figure of merit in a low-cost material, having an appreciable degree compatibility with the modern technology is required to convert waste heat into electrical energy efficiently. Using first-principles density functional theory and semiclassical Boltzmann transport theory, we report high performance silicon-based chalcogenide Si2Te3. Previously unknown ground state structure Si2Te3 was obtained by finding out 8 most energetically favorable sites for Si unit...
The Sm${}_{2}$Fe${}_{17}{X}_{3}$ compounds exhibit all the necessary magnetic properties for use as rare-earth-lean permanent magnets, which have been identified key to energy technology. However, thermodynamic instability of these materials thwarts their adoption in applications. authors' calculations show that doping with La or Ce generally maintains enhances properties, and substantially increases stability against $X$ vacancy formation. This points experimentalists right direction find...
Semiconducting transition metal dichalcogenides (TMDs) demonstrate a wide range of optoelectronic properties due to their diverse elemental compositions, and are promising candidates for next-generation optoelectronics energy harvesting devices. However, effective band offset engineering is required implement practical structures with desirable functionalities. Here, we explore the pressure-induced structure evolution monolayer WS2 Mo0.5W0.5S2 using hydrostatic compressive strain applied in...
Symmetry and dimensionality are essential factors defining lattice dynamics conductivity (\ensuremath{\kappa}). Here, we critically examine these via ab initio Boltzmann transport applied to single chain bulk electride $\mathrm{B}{\mathrm{a}}_{3}\mathrm{N}$ $\mathrm{B}{\mathrm{a}}_{3}\mathrm{N}X$ ($X=\mathrm{Sb}$,Bi). Chiral phonons in one-dimensional chains obey new symmetry-based scattering rules that limit thermal resistance. Weak coupling breaks the bulk, giving lower \ensuremath{\kappa}...
While pressure-induced changes in the electronic, magnetic, and optical properties of Cu-Cl hybrid perovskites have been studied intensively, correlation between these structural is still vaguely understood. Here, by first-principles calculations on a model system (EDBE)[CuCl4] (EDBE = 2,2'-(ethylenedioxy)bis(ethylammonium)) (a perovskite), we correlate evolution series exciting physical with pressure while resolving some long-standing debates fundamental electronic nature this important...
The wide measured range of thermal conductivities $(k)$ for monolayer ${\mathrm{MoS}}_{2}$ and the corresponding incongruent calculated values in literature all suggest that extrinsic defect resistance is significant varied synthesized samples this material. Here we present defect-mediated transport calculations using interatomic forces derived from density functional theory combined with Green's function methods to describe phonon-point-defect interactions a Peierls-Boltzmann formalism...
Using first principles based density functional calculation we study the mechanical, electronic and transport properties of single crystalline gold nanowires. While nanowires with diameter less than 2 nm retain hexagonal cross-section, larger wires show a structural smoothening leading to circular cross-section. These changes significantly affect mechanical wires, however, strength remains comparable bulk. The calculations reveal that conductivity these are in good agreement experiments....
Using first-principles density functional theory calculations, we show a semimetal to semiconducting electronic phase transition for bulk ${\mathrm{TiS}}_{2}$ by applying uniform biaxial tensile strain. This is triggered charge transfer from Ti S, which eventually reduces the overlap between Ti-$(d)$ and S-$(p)$ orbitals. The transport calculations large anisotropy in electrical conductivity thermopower, due difference effective masses along in-plane out-of-plane directions. Strain-induced...
Thermal conductivities of $\mathrm{L}{\mathrm{a}}_{3}\mathrm{C}{\mathrm{u}}_{3}{X}_{4}(X=\mathrm{P},\phantom{\rule{0.28em}{0ex}}\mathrm{As},\phantom{\rule{0.28em}{0ex}}\mathrm{Sb},\phantom{\rule{0.28em}{0ex}}\mathrm{Bi})$ compounds are examined using first-principles density functional theory and Boltzmann transport methods. We observe a trend increasing lattice thermal conductivity (${\ensuremath{\kappa}}_{l}$) with atomic mass, challenging our expectations, as lighter mass systems...