A5062426355- Luminescence Properties of Advanced Materials
- Electronic and Structural Properties of Oxides
- Quantum and electron transport phenomena
- Advanced Chemical Physics Studies
- 2D Materials and Applications
- Perovskite Materials and Applications
- Semiconductor materials and devices
- Inorganic Chemistry and Materials
- Surface and Thin Film Phenomena
- High-pressure geophysics and materials
- Machine Learning in Materials Science
- Physics of Superconductivity and Magnetism
- Solid-state spectroscopy and crystallography
- Diamond and Carbon-based Materials Research
- Superconductivity in MgB2 and Alloys
- Ga2O3 and related materials
- Ammonia Synthesis and Nitrogen Reduction
- Chalcogenide Semiconductor Thin Films
- ZnO doping and properties
- Experimental Learning in Engineering
- Advancements in Semiconductor Devices and Circuit Design
- E-Learning and Knowledge Management
- Metal and Thin Film Mechanics
- Organic and Molecular Conductors Research
- Quantum, superfluid, helium dynamics
UCLouvain
2011-2025
Walloon Excellence in Lifesciences and Biotechnology
2024-2025
European Theoretical Spectroscopy Facility
2013-2025
École Polytechnique Fédérale de Lausanne
2020-2023
University of Oxford
2016-2021
National University of Engineering
2020
Universidad de Bogotá Jorge Tadeo Lozano
2016
Belgian Nuclear Research Centre
2011
Quantum ESPRESSO is an integrated suite of open-source computer codes for quantum simulations materials using state-of-the art electronic-structure techniques, based on density-functional theory, perturbation and many-body within the plane-wave pseudo-potential projector-augmented-wave approaches. owes its popularity to wide variety properties processes it allows simulate, performance increasingly broad array hardware architectures, a community researchers that rely capabilities as core...
Abstract W annier90 is an open-source computer program for calculating maximally-localised Wannier functions (MLWFs) from a set of Bloch states. It interfaced to many widely used electronic-structure codes thanks its independence the basis sets representing these In past few years development has transitioned community-driven model; this resulted in number new developments that have been recently released v3.0. article we describe functionalities, include implementation features...
We probe the accuracy limit of ab initio calculations carrier mobilities in semiconductors, within framework Boltzmann transport equation. By focusing on paradigmatic case silicon, we show that fully predictive electron and hole require many-body quasiparticle corrections to band structures electron-phonon matrix elements, inclusion spin-orbit coupling, an extremely fine sampling inelastic scattering processes momentum space. considering all these factors obtain excellent agreement with...
One of the fundamental properties semiconductors is their ability to support highly tunable electric currents in presence fields or carrier concentration gradients. These are described by transport coefficients such as electron and hole mobilities. Recently, advances electronic structure methods for real materials have made it possible study these with predictive accuracy without resorting empirical parameters. Here, we review most recent developments area ab initio calculations mobilities...
Austenitic stainless steels are commonly used materials for in-core components of nuclear light water reactors. In service, such exposed to harsh conditions: intense neutron irradiation, mechanical and thermal stresses, aggressive corrosion environment which all contribute the components' degradation. For a better understanding prevailing mechanisms responsible degradation, large-scale atomistic simulations desirable. this framework we developed an embedded atom method type interatomic...
Halide perovskites constitute a new class of semiconductors that hold promise for low-cost solar cells and optoelectronics. One key property these materials is the electron mobility, which determines average speed due to driving electric field. Here we elucidate atomic-scale mechanisms theoretical limits carrier mobilities in halide by performing comparative analysis archetypal compound CH3NH3PbI3, its inorganic counterpart CsPbI3, classic semiconductor light-emitting diodes, wurtzite GaN,...
Abstract EPW is an open-source software for ab initio calculations of electron–phonon interactions and related materials properties. The code combines density functional perturbation theory maximally localized Wannier functions to efficiently compute coupling matrix elements, perform predictive temperature-dependent properties phonon-assisted quantum processes in bulk solids low-dimensional materials. Here, we report on significant developments the since 2016, namely: a transport module...
The renormalization of electronic eigenenergies due to electron-phonon coupling (temperature dependence and zero-point motion effect) is sizable in many materials with light atoms. This effect, often neglected ab initio calculations, can be computed using the perturbation-based Allen-Heine-Cardona theory adiabatic or non-adiabatic harmonic approximation. After a short description recent progresses this field brief overview theory, we focus on issue phonon wavevector sampling convergence,...
We compute the zero-point renormalization (ZPR) of optical band gap diamond from many-body perturbation theory using perturbative ${G}_{0}{W}_{0}$ approximation as well quasiparticle self-consistent $GW$. The electron-phonon coupling energies are found to be more than 40% higher standard density functional when effects included with frozen-phonon calculations. A similar increase is observed for in GaAs corrections applied. show that these necessary accurately predict temperature dependence...
We elucidate the origin of phonon-mediated superconductivity in $2H$-${\mathrm{NbS}}_{2}$ using ab initio anisotropic Migdal-Eliashberg theory including Coulomb interactions. demonstrate that is associated with Fermi surface hot spots exhibiting an unusually strong electron-phonon interaction. The electron-lattice coupling dominated by low-energy anharmonic phonons, which place system on verge a charge density wave instability. also provide definitive evidence for two-gap...
For a set of ten crystalline materials (oxides and semiconductors), we compute the electronic band structures using Tran-Blaha [Phys. Rev. Lett. 102, 226401 (2009)] (TB09) functional. The widths gaps are compared with those from local-density approximation (LDA) functional, many-body perturbation theory (MBPT), experiments. At density-functional (DFT) level, TB09 leads to in much better agreement experiments than LDA. However, observe that it globally underestimates, often strongly, valence...
Environmental effects and intrinsic energy-loss processes lead to fluctuations in the operational temperature of solar cells, which can profoundly influence their power conversion efficiency. Here we determine from first-principles on band gap edges hybrid pervoskite CH3NH3PbI3 by accounting for electron-phonon coupling thermal expansion. From 290 380 K, computed change 40 meV coincides with experimental 30-40 meV. The calculation is particularly intricate as commonly used...
A new method enables $a\phantom{\rule{0}{0ex}}b\phantom{\rule{0.333em}{0ex}}i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}o$ calculations of large and small polarons on the same footing. The authors develop theory computational methodology required to determine ground-state energy wave functions electron hole in semiconductors insulators, without performing explicit supercell calculations. As initial applications,...
The renormalization of the band structure at zero temperature due to electron-phonon coupling is explored in diamond, BN, LiF, and MgO crystals. We implement a dynamical scheme compute frequency-dependent self-energy resulting quasiparticle electronic structure. Our calculations reveal presence satellite below Fermi level LiF MgO. show that factor $(Z)$, which neglected adiabatic approximation, can reduce zero-point (ZPR) by as much $40%$. Anharmonic effects renormalized eigenvalues finite...
We develop a formalism and computational method to study polarons in insulators semiconductors from first principles. Unlike standard calculations requiring large supercells, we solve secular equation involving phonons electron-phonon matrix elements density-functional perturbation theory, spirit similar the Bethe-Salpeter for excitons. show that our approach describes seamlessly small polarons, illustrate its capability by calculating wave functions, formation energies, spectral...
The renormalization of electronic eigenenergies due to electron-phonon interactions (temperature dependence and zero-point motion effect) is important in many materials. We address it the adiabatic harmonic approximation, based on first principles (e.g., density-functional theory), from different points view: directly atomic position fluctuations or, alternatively, Janak's theorem generalized case where Helmholtz free energy, including vibrational entropy, used. prove their equivalence,...
Nitride semiconductors are ubiquitous in optoelectronic devices such as LEDs and Blu-Ray optical disks. A major limitation for further adoption of GaN power electronics is its low hole mobility. In order to address this challenge, here we investigate the phonon-limited mobility wurtzite using ab initio Boltzmann transport formalism, including all electron-phonon scattering processes, spin-orbit coupling, many-body quasiparticle band structures. We demonstrate that dominated by acoustic...
Two-dimensional (2D) semiconductors are at the center of an intense research effort aimed developing next generation flexible, transparent, and energy-efficient electronics. In these applications, carrier mobility, that is ability electrons holes to move rapidly in response external voltage, a critical design parameter. Here, we show interlayer coupling between electronic wave functions 2D can be used drastically alter mobility dynamics. We demonstrate this concept by performing...
We elucidate the nature of electron-phonon interaction in archetypal hybrid perovskite CH_{3}NH_{3}PbI_{3} using ab initio many-body calculations and an exactly solvable model. demonstrate that electrons holes near band edges primarily interact with three distinct groups longitudinal-optical vibrations, order importance: stretching Pb-I bond, bending Pb-I-Pb bonds, libration organic cations. These polar phonons induce ultrafast intraband carrier relaxation over timescales 6-30 fs yield...
A fundamental obstacle toward the realization of GaN p-channel transistors is its low hole mobility. Here we investigate intrinsic phonon-limited mobility electrons and holes in wurtzite using ab initio Boltzmann transport formalism, including all electron-phonon scattering processes many-body quasiparticle band structures. We predict that can be increased by reversing sign crystal-field splitting such a way as to lift split-off states above light heavy holes. find 2% biaxial tensile strain...
Significant progress on parameter-free calculations of carrier mobilities in real materials has been made during the past decade; however, role various approximations remains unclear and a unified methodology is lacking. Here, we present analyse comprehensive efficient approach to compute intrinsic, phonon-limited drift Hall semiconductors, within framework first-principles Boltzmann transport equation. The exploits novel for estimating quadrupole tensors including them electron-phonon...
Semiconducting polycrystalline thin films are cheap to produce and can be deposited on flexible substrates, yet high-performance electronic devices usually utilize single-crystal semiconductors, owing their superior electrical mobilities longer diffusion lengths. Here we show that the performance of metal-halide perovskites (MHPs) approaches single crystals at room temperature. Combining temperature-dependent terahertz conductivity measurements ab initio calculations uncover a complete...