A5044060021- Advanced Chemical Physics Studies
- Fullerene Chemistry and Applications
- Carbon Nanotubes in Composites
- Machine Learning in Materials Science
- Molecular Junctions and Nanostructures
- Graphene research and applications
- Boron and Carbon Nanomaterials Research
- Advanced Physical and Chemical Molecular Interactions
- Superconductivity in MgB2 and Alloys
- High-pressure geophysics and materials
- Scientific Research and Discoveries
- Quantum and electron transport phenomena
- Inorganic Chemistry and Materials
- Surface and Thin Film Phenomena
- Electron and X-Ray Spectroscopy Techniques
- Semiconductor materials and devices
- Chemical and Physical Properties of Materials
- Nonlinear Optical Materials Research
- Advancements in Semiconductor Devices and Circuit Design
- Spectroscopy and Quantum Chemical Studies
- Particle accelerators and beam dynamics
- Chemical Reactions and Mechanisms
- Physics of Superconductivity and Magnetism
- Thermal Radiation and Cooling Technologies
- Underground infrastructure and sustainability
UCLouvain
2014-2017
European Theoretical Spectroscopy Facility
2015-2017
Universidad de Bogotá Jorge Tadeo Lozano
2016
Université de Montréal
2010-2015
Regroupement Québécois sur les Matériaux de Pointe
2010-2015
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,...
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,...
We study the electron-phonon coupling in C60 fullerene within first-principles GW approach, focusing on lowest unoccupied t1u three-fold electronic state which is relevant for superconducting transition electron doped fullerides. It shown that strength of significantly enhanced as compared to standard density functional theory calculations with (semi)local functionals, a 48% increase potential Vep. The calculated value contribution from Hg modes 93 meV comes 4% most recent experimental...
The knowledge of effective masses is a key ingredient to analyze numerous properties semiconductors, like carrier mobilities, (magneto-)transport properties, or band extrema characteristics yielding densities and density states. Currently, these are usually calculated using finite-difference estimation functional theory (DFT) electronic curvatures. However, finite differences require an additional convergence study prone numerical noise. Moreover, the concept mass breaks down at degenerate...
The calculations of the electron-phonon coupling in ${\text{C}}_{60}$ molecules are analyzed context hybrid functionals within density-functional theory (DFT) approach. We find that increasing contribution exchange energy calculated with a Fock operator functional from 0 to 30% has little impact on structural properties and phonon frequencies, but it generates strong increase total $(\ensuremath{\sim}40\mathrm{%})$. resulting couplings for each vibrational mode better agreement experimental...
We present a ${G}_{0}{W}_{0}$ implementation that assesses the two major bottlenecks of traditional plane-waves implementations, summations over conduction states and inversion dielectric matrix, without introducing new approximations in formalism. The first bottleneck is circumvented by converting into Sternheimer equations. Then, novel avenue expressing matrix Lanczos basis developed, which reduces size orders magnitude while being computationally efficient. also develop model operator...
Covalent addition of functional groups onto carbon nanotubes is known to generate lattice point defects that disrupt the electronic wave function, resulting namely in a reduction their optical response and electrical conductance. Here, conductance measurements combined with numerical simulations are used unambiguously identify presence graft-induced midgap states structure covalently functionalized semiconducting nanotubes. The main experimental evidence an increase OFF-state after covalent...
We study the thermodynamics of bromophenyl functionalization carbon nanotubes with respect to diameter and metallic/insulating character using density-functional theory (DFT). On one hand, we show that metallic is thermodynamically favoured over semiconducting ones, in agreement what binding energy calculations previously suggested. other activation for grafting a molecule onto zigzag nanotube ranges from 0.72 0.75 eV without any clear dependence within numerical accuracy. This implies this...
Recommender systems are an important component in the retail industry, but constantly renewed inventory of many companies makes it difficult to aggregate enough data fully harness benefits such systems. In this paper, we describe a technique that significantly improves accuracy recommendations, validated on real store transaction history, by performing time translation maps out-of-stock items similar currently stock using deep features products. This greatly reduces dimension item-item...
The renormalization of electronic eigenenergies due to electron-phonon coupling 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 numerous recent progresses this field, and brief overview theory, we focus on issue phonon wavevector sampling convergence, until now poorly understood. Indeed,...