Publications related to Polaron

Nonempirical semilocal density functionals for correcting the self-interaction of polaronic states

Through the use of the piecewise-linearity condition of the total energy, we correct the self-interaction for the study of polarons by constructing nonempirical functionals at the semilocal level of theory. We consider two functionals, the gamma DFT and mu ...

Aip Publishing2024

Polaron hopping through piecewise-linear functionals

Alfredo Pasquarello, Stefano Falletta

We use piecewise-linear functionals to study the polaron energy landscape and hopping rates in beta-Ga2O3, which we adopt as an example of an anisotropic material hosting multiple polaronic states. We illustrate various functionals for polaron localization ...

AMER PHYSICAL SOC2023

Self-Interaction and Polarons in Density Functional Theory

Stefano Falletta

The electron self-interaction is a long-standing problem in density functional theory and is particularly critical in the description of polarons. Polarons are quasiparticles involving charge localization coupled with self-induced lattice distortions. Sinc ...

EPFL2023

Electron-phonon driven unconventional superconductivity: The role of small Fermi energies and of nonadiabatic processes

Claudio Grimaldi

The very concept of high-T-c superconductivity has originated from the discovery of superconductivity in copper oxides by Bednorz and Muller in 1986. Soon after their discovery, cuprates were recognized as undoubtedly complex and radically unconventional s ...

Elsevier2023

Polarons free from many-body self-interaction in density functional theory

Alfredo Pasquarello, Stefano Falletta

We develop a unified theoretical framework encompassing one-body and many-body forms of self-interaction. We find an analytic expression for both the one-body and the many-body self-interaction energies, and quantitatively connect the two expressions throu ...

2022

Hubbard U through polaronic defect states

Alfredo Pasquarello, Stefano Falletta

Since the preliminary work of Anisimov and co-workers, the Hubbard corrected DFT+U functional has been used for predicting properties of correlated materials by applying on-site effective Coulomb interactions to specific orbitals. However, the determinatio ...

NATURE PORTFOLIO2022

Evidence of a coupled electron-phonon liquid in NbGe2

Mathieu François Padlewski, Matthias Carsten Putzke, Philip Johannes Walter Moll, Hao Yang

Whereas electron-phonon scattering relaxes the electron's momentum in metals, a perpetual exchange of momentum between phonons and electrons may conserve total momentum and lead to a coupled electron-phonon liquid. Such a phase of matter could be a platfor ...

Nature Portfolio2021

Interaction of Confined Polaritons in Microcavity Structures

Morteza Navadeh Toupchi

A polariton is a quasiparticle formed from the coupling of a confined photon in a cavity to electronic excitation, like exciton in a semiconductor. This dissertation reports on series of experiments in confined polariton interaction by design, fabrication, ...

EPFL2021

Ab Initio Electron-Phonon Interactions in Correlated Electron Systems

Nicola Marzari, Iurii Timrov, Matteo Cococcioni, Andrea Floris

Electron-phonon (e-ph) interactions are pervasive in condensed matter, governing phenomena such as transport, superconductivity, charge-density waves, polarons, and metal-insulator transitions. First-principles approaches enable accurate calculations of e- ...

AMER PHYSICAL SOC2021

Direct measurement of key exciton properties: Energy, dynamics, and spatial distribution of the wave function

Michele Puppin, Martin Wolf

Excitons, Coulomb-bound electron-hole pairs, are the fundamental excitations governing the optoelectronic properties of semiconductors. Although optical signatures of excitons have been studied extensively, experimental access to the excitonic wave functio ...

Wiley2021

Time- and Angle-Resolved Photoelectron Spectroscopy of Solar Materials

Serhii Polishchuk

Natural foundations defining the manner in which a solid material interacts with optical radiation are primarily encoded in the material's momentum-dependent band structure and the microscopic details of the electron-lattice interactions. An access to this ...

EPFL2021

Profiling novel high-conductivity 2D semiconductors

Nicola Marzari, Marco Gibertini, Thibault Daniel Pierre Sohier

When complex mechanisms are involved, pinpointing high-performance materials within large databases is a major challenge in materials discovery. We focus here on phonon-limited conductivities, and study 2D semiconductors doped by field effects. Using state ...

IOP PUBLISHING LTD2021

Resonant Inelastic X-ray Scattering Studies of Low-Dimensional and Frustrated 3d Transition-Metal Oxides

Yi Tseng

3d transition-metal oxide materials with strong electron correlations and low dimensionality give rise to emerging exotic phases. Resonant inelastic X-ray scattering (RIXS) has developed as a powerful spectroscopic tool for probing the collective excitatio ...

EPFL2021

Evidence for a spin acoustic surface plasmon from inelastic atom scattering

Davide Campi

Closed-shell atoms scattered from a metal surface exchange energy and momentum with surface phonons mostly via the interposed surface valence electrons, i.e., via the creation of virtual electron-hole pairs. The latter can then decay into surface phonons v ...

Nature Research2021

Evidence of Large Polarons in Photoemission Band Mapping of the Perovskite Semiconductor CsPbBr3

Majed Chergui, Nicola Marzari, Marco Grioni, Nicola Colonna, Michele Puppin, Matthias Wolf, Alberto Crepaldi, Gianmarco Gatti, Serhii Polishchuk, Thomas Roland Barillot, Riccardo De Gennaro

Lead-halide perovskite (LHP) semiconductors are emergent optoelectronic materials with outstanding transport properties which are not yet fully understood. We find signatures of large polaron formation in the electronic structure of the inorganic LHP CsPbB ...

AMER PHYSICAL SOC2020

Small Electron Polarons in CsPbBr3: Competition between Electron Localization and Delocalization

Alfredo Pasquarello, Stefano Falletta, Julia Anna Wiktor

We study the nature of excess electrons in CsPbBr3 and identify several single and double polaronic states. We emphasize the importance of proper inclusion of the self-interaction corrections for the stability of small electron polarons in this material. W ...

AMER CHEMICAL SOC2020

Computational Modeling of the Oxygen Evolution Reaction at Semiconductor-Water Interfaces: A Path Towards Breaking Linear Scaling Relationships

Patrick Gono

Photoelectrochemical water splitting is a promising source of clean, renewable fuel in the form of hydrogen. Despite extensive research endeavors, the widespread adoption of this technology is impeded due to suboptimal catalysts for the oxygen evolution re ...

EPFL2020

Electron-phonon-driven three-dimensional metallicity in an insulating cuprate

Fabrizio Carbone, Edoardo Baldini, Cédric Weber

The role of the crystal lattice for the electronic properties of cuprates and other high-temperature superconductors remains controversial despite decades of theoretical and experimental efforts. While the paradigm of strong electronic correlations suggest ...

National Academy of Sciences2020

Terahertz surface modes and electron-phonon coupling on Bi2Se3(111)

Davide Campi

We present a combined experimental and theoretical study of the surface vibrational modes of the topological insulator Bi2Se3 with particular emphasis on the low-energy region below 10 meV that has been difficult to resolve experimentally. By applying inel ...

AMER PHYSICAL SOC2020

Exciton and Carrier Dynamics in Two-Dimensional Perovskites

Jacques-Edouard Moser, Etienne Christophe Socie, Marine Eva Fedora Bouduban, Andrés Burgos Caminal

Two-dimensional Ruddlesden−Popper hybrid lead halide perovskites have become a major topic in perovskite optoelectronics. Here, we aim to unravel the ultrafast dynamics governing the evolution of charge carriers and excitons in these materials. Using a com ...

2020