A5064664549- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Advanced Chemical Physics Studies
- Magnetic and transport properties of perovskites and related materials
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- High-pressure geophysics and materials
- Electronic and Structural Properties of Oxides
- 2D Materials and Applications
- Boron and Carbon Nanomaterials Research
- Machine Learning in Materials Science
- Magnetic properties of thin films
- Chalcogenide Semiconductor Thin Films
- Multiferroics and related materials
- Graphene research and applications
- Topological Materials and Phenomena
- Particle Detector Development and Performance
- ZnO doping and properties
- Solid-state spectroscopy and crystallography
- Advanced Condensed Matter Physics
- Surface and Thin Film Phenomena
- Quantum and electron transport phenomena
- Rare-earth and actinide compounds
- Physics of Superconductivity and Magnetism
West Virginia University
2016-2025
University of Luxembourg
2022-2024
Universidad de Granada
2024
Benemérita Universidad Autónoma de Puebla
2013-2022
Industrial University of Santander
2022
University of Turin
2002-2020
Istituto Nazionale di Fisica Nucleare, Sezione di Torino
1988-2020
Central American Technological University
2020
Università degli Studi del Piemonte Orientale “Amedeo Avogadro”
2019-2020
Universidad Metropolitana de Honduras
2020
We have performed first-principles calculations of the electronic structure ZnO, and applied them to determination structural lattice-dynamical properties their dependence on pressure. The dynamical matrices been obtained for wurtzite, zinc-blende, rocksalt modifications with several lattice parameters optimized pressures up 12 GPa. These are employed calculate one-phonon densities states (DOS) two-phonon DOS associated either sums or differences phonons. results provide essential tools...
Anomalous Raman modes have been reported in several recent papers dealing with doped- and undoped-ZnO layers grown by different methods. Most of these anomalous attributed to local vibrational impurities or defects. However, we will show that most the observed correspond wurtzite-ZnO silent allowed breakdown translational crystal symmetry induced defects impurities.
abinit is probably the first electronic-structure package to have been released under an open-source license about 20 years ago. It implements density functional theory, density-functional perturbation theory (DFPT), many-body (GW approximation and Bethe–Salpeter equation), more specific or advanced formalisms, such as dynamical mean-field (DMFT) “temperature-dependent effective potential” approach for anharmonic effects. Relying on planewaves representation of wavefunctions, density, other...
Recent advances in the theory of polarization and development linear-scaling methods have revitalized interest use Wannier functions for obtaining a localized orbital picture within periodic supercell. To examine complex chemical systems it is imperative localization procedure to be efficient; on other hand, method should also simple general. Motivated meet these requirements we derive this paper spread functional minimized as starting point maximally through unitary transformation. The...
We present a numerical study of classical particles diffusing on solid surface. The particles' motion is modeled by an underdamped Langevin equation with ordinary thermal noise. particle-surface interaction described periodic or random two dimensional potential. model leads to rich variety different transport regimes, some which correspond anomalous diffusion such as has recently been observed in experiments and Monte Carlo simulations. show that this behavior controlled the friction...
The search for novel two-dimensional giant Rashba semiconductors is a crucial step in the development of forthcoming nanospintronic technology. Using first-principles calculations, we study stable crystal phase BiSb having buckled honeycomb lattice geometry, which yet unexplored. phonon, room temperature molecular dynamics, and elastic constant calculations verify dynamical mechanical stability monolayer at 0 K temperature. calculated electronic band structure reveals direct gap...
Ultrathin passive films effectively prevent the chemical attack of stainless steel grades in corrosive environments; their stability depends on interplay between structure and chemistry constituents iron, chromium, molybdenum (Fe-Cr-Mo). Carbon (C), eventually boron (B), are also important steels, although small quantities. In particular, nanoscale inhomogeneities along surface can have an impact material failure but still poorly understood. Addressing a stainless-type glass-forming...
We have theoretically investigated, by ab initio techniques, the phonon properties of several semiconductors with chalcopyrite structure. Comparison experiments has led us to distinguish between materials $d$ electrons in valence band (e.g., CuGaS${}_{2}$, AgGaS${}_{2}$) and those without ZnSnAs${}_{2}$). The former exhibit a rather peculiar nonmonotonic temperature dependence energy gap which, so far, resisted cogent theoretical description. analyze this fitting two Bose-Einstein...
We systematically investigate the excitonic dephasing of three representative transition-metal dichalcogenides, namely, ${\mathrm{MoS}}_{2}$, ${\mathrm{MoSe}}_{2}$, and ${\mathrm{WSe}}_{2}$ atomic monolayer thick bulk crystals, in order to gain a proper understanding factors that determine optical coherence these materials. Coherent nonlinear spectroscopy temperature dependent absorption, combined with theoretical calculations phonon spectra, indicate electron-phonon interactions, be...
We investigate the harmonic and anharmonic contributions to phonon spectrum of lead telluride perform a complete characterization how thermal properties PbTe evolve as temperature increases. analyze resistivity's variation with clarify misconceptions about existing experimental literature. The resistivity initially increases sublinearly because phase space effects ultra strong renormalizations specific bands. This effect is strongest factor in favorable thermoelectric PbTe, it explains its...
Graphene/MoS$_2$ van der Waals (vdW) heterostructures have promising technological applications due to their unique properties and functionalities. Many experimental theoretical research groups across the globe made outstanding contributions benchmark of graphene/MoS$_2$ heterostructures. Even though some already an attempt model using {\it first-principles} calculations, there exists several discrepancies in results from different findings. In present work, we revisit this problem by first...
The interest in improving the thermoelectric response of bulk materials has received a boost after it been recognized that layered materials, particular SnSe, show very large figure merit. This result great attention while is now possible to conceive other similar or experimental methods improve this value. Before we can think engineering material important understand basic mechanism explains unusual behavior, where low thermal conductivity and high thermopower from delicate balance between...
Recently published discoveries of acoustic and optical mode inversion in the phonon spectrum certain metals became first realistic example non-interacting topological bosonic excitations existing materials. However, observable physical technological use such phases remained unclear. In this work we provide a strong theoretical numerical evidence that for class metallic compounds (known as triple point metals), points spectrum, at which three (two one acoustic) modes (bands) cross, represent...
Using first-principles calculations, we systematically study the elastic stiffness constants, mechanical properties, wave velocities, Debye temperature, melting and specific heat of several thermodynamically stable crystal structures ${\mathrm{Bi}}_{x}{\mathrm{Sb}}_{1\ensuremath{-}x}$ ($0<x<1$) binaries, which are great interest due to their numerous inherent rich such as thermoelectricity, thermomagnetic cooling, strong spin-orbit coupling (SOC) effects, topological features in electronic...
Abstract Lack of rigorous reproducibility and validation are significant hurdles for scientific development across many fields. Materials science, in particular, encompasses a variety experimental theoretical approaches that require careful benchmarking. Leaderboard efforts have been developed previously to mitigate these issues. However, comprehensive comparison benchmarking on an integrated platform with multiple data modalities perfect defect materials is still lacking. This work...
The Rashba spin–orbit coupling effect, primarily arising from structural-inversion asymmetry in periodic crystals, has garnered considerable attention due to its tunability and potential applications spintronics. Its capability manipulate electron spin without an external magnetic field opens new avenues for spintronic device design, particularly semiconductor technology. Within this framework, 2D materials hold special interest their inherent characteristics, which facilitate...
Phonon linewidths can exhibit a large variation when either pressure or isotopic masses are changed. These effects yield detailed information about the mechanisms responsible for and lifetimes, e.g., anharmonicity disorder. We report Raman measurements of linewidth upper ${\mathrm{E}}_{2}$ phonons ZnO crystals with several compositions their dependence on pressure. Changes by factor 12 observed at given temperature. Comparison calculated densities one-phonon states, isotope scattering,...
Hydrogen bonds in H2O ice change dramatically upon compression. Thereby a hydrogen-bonded molecular crystal, VII, is transformed to an atomic X. Car-Parrinello simulations reproduce the features of x-ray diffraction spectra up about 170 GPa but allow for analysis real space. Starting from VII with static orientational disorder, dynamical translational disordering occurs first via creation ionic defects, which results systematic violation rules. As second step, transformation solid and thus...
The structural, energetic, and electronic properties of the Li/graphite system are studied through density functional theory (DFT) calculations using both local spin approximation (LSDA), gradient-corrected Perdew-Burke-Ernzerhof (PBE) to exchange-correlation energy. were performed plane waves basis, electron-core interactions described pseudopotentials. We consider a disperse phase adsorbate comprising one Li atom for each 16 graphite surface cells, in slab geometry. close contact between...
Zinc oxide is a key material for optoelectronic applications, whose transport properties are typically dominated by the lattice vibrations. We report here phonon-dispersion relations of wurtzite ZnO at 10 K, as determined using inelastic neutron scattering. The experimental data analyzed with aid ab initio calculations based on density-functional perturbation theory. A complete picture dynamics drawn from present results, thus contributing to understanding mechanical, thermodynamical, and materials.