Publications de Samuel Poncé | EPFL Graph Search

Phonon Self-Energy Corrections: To Screen, or Not to Screen

First-principles calculations of phonons are often based on the adiabatic approximation and on Brillouinzone samplings that might not always be sufficient to capture the subtleties of Kohn anomalies. These shortcomings can be addressed through corrections ...

American Physical Society2023

Long-range electrostatic contribution to electron-phonon couplings and mobilities of two-dimensional and bulk materials

Massimiliano Stengel, Nicola Marzari, Marco Gibertini, Samuel Poncé

Charge transport plays a crucial role in manifold potential applications of two-dimensional materials, in-cluding field-effect transistors, solar cells, and transparent conductors. At most operating temperatures, charge transport is hindered by scattering ...

AMER PHYSICAL SOC2023

Electronic Structure of Few-Layer Black Phosphorus from & mu;-ARPES

Christophe Berthod, Nicola Marzari, Marco Gibertini, Samuel Poncé

Black phosphorus (BP) stands out among two-dimensional(2D) semiconductorsbecause of its high mobility and thickness dependent direct band gap.However, the quasiparticle band structure of ultrathin BP has remainedinaccessible to experiment thus far. Here we ...

AMER CHEMICAL SOC2023

General invariance and equilibrium conditions for lattice dynamics in 1D, 2D, and 3D materials

Nicola Marzari, Samuel Poncé, Changpeng Lin

The long-wavelength behavior of vibrational modes plays a central role in carrier transport, phonon-assisted optical properties, superconductivity, and thermomechanical and thermoelectric properties of materials. Here, we present general invariance and equ ...

NATURE PORTFOLIO2022

Ultrafast photo-induced phonon hardening due to Pauli blocking in MAPbI(3) single-crystal and polycrystalline perovskites

Feliciano Giustino, Samuel Poncé

Metal-halide perovskite semiconductors have attracted intense interest over the past decade, particularly for applications in photovoltaics. Low-energy optical phonons combined with significant crystal anharmonicity play an important role in charge-carrier ...

IOP PUBLISHING LTD2021

Common workflows for computing material properties using different quantum engines

Sebastiaan Philippe Huber, Nicola Marzari, Gian-Marco Rignanese, Giovanni Pizzi, Aliaksandr Yakutovich, Berend Smit, Martin Uhrin, Conrad Johnston, Austin Jacob Zadoks, Samuel Poncé, Kristjan Eimre, Marnik Bercx, Christopher John Sewell

The prediction of material properties based on density-functional theory has become routinely common, thanks, in part, to the steady increase in the number and robustness of available simulation packages. This plurality of codes and methods is both a boon ...

2021

Virtual Computational Chemistry Teaching Laboratories-Hands-On at a Distance

Nicola Marzari, Giovanni Pizzi, Iurii Timrov, Christoph Leopold Talirz, Francisco Fernando Ramirez, Samuel Poncé, Marnik Bercx

The COVID-19 pandemic disrupted chemistry teaching practices globally as many courses were forced online, necessitating adaptation to the digital platform. The biggest impact was to the practical component of the chemistry curriculum-the so-called wet lab. ...

AMER CHEMICAL SOC2021

First-principles predictions of Hall and drift mobilities in semiconductors

Nicola Marzari, Samuel Poncé

Carrier mobility is at the root of our understanding of electronic devices. We present a unified methodology for the parameter-free calculations of phonon-limited drift and Hall carrier mobilities in real materials within the framework of the Boltzmann tra ...

AMER PHYSICAL SOC2021

Importance of Long-Range Channel Sr Displacements for the Narrow Emission in Sr[Li2Al2O2N2]:Eu2+ Phosphor

Samuel Poncé

The recently discovered Sr[Li2Al2O2N2]:Eu2+ red phosphor, candidate for the next generation of eco-efficient white light-emitting diodes, exhibits excellent emission spectral position and exceptionally small linewidth. It belongs to the UCr4C4-structure fa ...

WILEY-V C H VERLAG GMBH2021

Limits to Electrical Mobility in Lead-Halide Perovskite Semiconductors

Samuel Poncé

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 to their superior charge-carrier mobilities and longer ...

2021

Wannier90 as a community code: new features and applications

Nicola Marzari, Giovanni Pizzi, Marco Gibertini, Lorenzo Paulatto, Hyungjun Lee, Daniel John Gilles Marchand, Antimo Marrazzo, Samuel Poncé, Junfeng Qiao

Wannier90 is an open-source computer program for calculating maximally-localised Wannier functions (MLWFs) from a set of Bloch states. It is interfaced to many widely used electronic-structure codes thanks to its independence from the basis sets representi ...

2020

Structural, electronic, elastic, power, and transport properties of beta-Ga2O3 from first principles

Feliciano Giustino, Samuel Poncé

We investigate the structural, electronic, vibrational, power, and transport properties of the beta allotrope of Ga2O3 from first principles. We find phonon frequencies and elastic constants that reproduce the correct band ordering, in agreement with exper ...

2020

First-principles calculations of charge carrier mobility and conductivity in bulk semiconductors and two-dimensional materials

Feliciano Giustino, Samuel Poncé

One of the fundamental properties of semiconductors is their ability to support highly tunable electric currents in the presence of electric fields or carrier concentration gradients. These properties are described by transport coefficients such as electro ...

IOP PUBLISHING LTD2020

Superconducting properties of MoTe2 from ab initio anisotropic Migdal-Eliashberg theory

Feliciano Giustino, Samuel Poncé

Molybdenum ditelluride (MoTe2) is attracting considerable interest since it is the archetypal type-II Weyl semimetal and a candidate for topological superconductivity. We investigate the superconducting phase diagram of two MoTe2 polymorphs using the ab in ...

AMER PHYSICAL SOC2020

Design rule for the emission linewidth of Eu 2+-activated phosphors

Samuel Poncé

ELSEVIER2020

Theory and Computation of Hall Scattering Factor in Graphene

Feliciano Giustino, Samuel Poncé

The Hall scattering factor, r, is a key quantity for establishing carrier concentration and drift mobility from Hall measurements; in experiments, it is usually assumed to be 1. In this paper, we use a combination of analytical and ab initio modeling to de ...

AMER CHEMICAL SOC2020