Publications associées à Structure and Energy of Charged Domain Walls in Ferroelectrics

Light-Induced Renormalization of the Dirac Quasiparticles in the Nodal-Line Semimetal ZrSiSe

Helmuth Berger, Philippe Bugnon, Marco Grioni, Majed Chergui, Arnaud Magrez, Luca Moreschini, Alberto Crepaldi, Simon Karl Moser, Gianmarco Gatti, Serhii Polishchuk, Michele Puppin

In nodal-line semimetals, linearly dispersing states form Dirac loops in the reciprocal space with a high degree of electron-hole symmetry and a reduced density of states near the Fermi level. The result is reduced electronic screening and enhanced correla ...

2020

Enhanced Electron-Phonon Interaction in Multivalley Materials

Helmuth Berger, Nicola Marzari, Evgeniy Ponomarev, Marco Gibertini, Thibault Daniel Pierre Sohier

We report a combined experimental and theoretical investigation that reveals a new mechanism responsible for the enhancement of electron-phonon coupling in doped semiconductors in which multiple inequivalent valleys are simultaneously populated. Using Rama ...

American Physical Society2019

Identification of Semiconductor Defects through Constant-Fermi-Level Ab Initio Molecular Dynamics: Application to GaAs

Alfredo Pasquarello, Assil Bouzid

We show that constant-Fermi-level ab initio molecular dynamics can be used as a computer-based tool to reveal and control relevant defects in semiconductor materials. In this scheme, the Fermi level can be set at any position within the band gap during the ...

American Physical Society (APS)2017

Monitoring Charge Carrier Dynamics at Atomic Length Scales by STM-induced Luminescence

Christoph Grosse

The goal of this thesis is the combination of the high spatial resolution of scanning tunneling microscopy (STM) with the high temporal resolution of optical spectroscopy, by monitoring the light emitted from the tunnel junction. Two complementary techniqu ...

EPFL2015

Controlling edge states in the Kane-Mele model via edge chirality

Oleg Yazyev, Gabriel Albert Autes

We investigate the dependence of band dispersion of the quantum spin Hall effect (QSHE) edge states in the Kane-Mele model on crystallographic orientation of the edges. Band structures of the one-dimensional honeycomb lattice ribbons show the presence of t ...

Wiley-V C H Verlag Gmbh2013

Ultrafast photodoping and effective Fermi-Dirac distribution of the Dirac particles in Bi2Se3

Helmuth Berger, Philippe Bugnon, Klaus Kern, Marco Grioni, Alberto Crepaldi

We exploit time- and angle-resolved photoemission spectroscopy to determine the evolution of the out-of-equilibrium electronic structure of the topological insulator Bi2Se3. The response of the Fermi-Dirac distribution to ultrashort IR laser pulses has bee ...

Amer Physical Soc2012