Publications related to Modeling Stressed MOS Oxides Using a Multiphonon-Assisted Quantum Approach—Part II: Transient Effects

Murunskite - a new class of functional material

The subject of the present work is discovery and in-depth characterization of a new class of functional materials. Tuning of the bond polarity and orbital occupation with a goal of establishing balance between localization and delocalization of electrons - ...

EPFL2023

From hidden order to antiferromagnetism: Electronic structure changes in Fe-doped URu2Si2

Emmanouil Frantzeskakis, Kevin Huang, Ji Dai

In matter, any spontaneous symmetry breaking induces a phase transition characterized by an order parameter, such as the magnetization vector in ferromagnets, or a macroscopic many electron wave function in superconductors. Phase transitions with unknown o ...

National Academy of Sciences2021

Extremely large magnetoresistance in the "ordinary" metal ReO3

Oleg Yazyev, Quansheng Wu, Shengnan Zhang, Huancheng Chen

The extremely large magnetoresistance (XMR) observed in many topologically nontrivial and trivial semimetals has attracted much attention in relation to its underlying physical mechanism. In this paper, by combining the band structure and Fermi surface (FS ...

AMER PHYSICAL SOC2021

Enhancement Mode Tri-gate GaN Power Devices and Logic Circuits

Minghua Zhu

Gallium Nitride (GaN) is one of the most promising materials for high frequency power switching due to its exceptional properties such as large saturation velocity, high carrier mobility, and high breakdown field strength. The high switching frequency of G ...

EPFL2021

Electrons leave the flatland: out-of-plane charge dynamics in layered materials

Edoardo Martino

The goal of this thesis is to explore the "neglected" third dimension of layered materials, by studying the interlayer charge dynamics through dc conductivity, optical spectroscopy and ab-initio calculations. This project was designed to respond to the gro ...

EPFL2020

Controlling magnetic order, magnetic anisotropy, and band topology in the semimetals Sr(Mn0.9Cu0.1)Sb-2 and Sr(Mn0.9Zn0.1)Sb-2

Yong Liu

Neutron diffraction and magnetic susceptibility studies show that orthorhombic single-crystals of topological semimetals Sr(Mn0.9Cu0.1)Sb-2 and Sr(Mn0.9Zn0.1)Sb-2 undergo three-dimensional C-type antiferromagnetic (AFM) ordering of the Mn2+ moments at T-N ...

2020

Photocarrier-induced band-gap renormalization and ultrafast charge dynamics in black phosphorus

Marco Grioni, Majed Chergui, Steven Roth, Alberto Crepaldi, Gianmarco Gatti, Michele Puppin

With its tunable band-gap and its unique optical and electronic properties black phosphorus (BP) opens exciting opportunities for optoelectronic nanotechnology. The band-gap extends from the visible to the mid-infrared spectral range, as a function of samp ...

2019

Reduction of Fermi level pinning at Cu-BP interfaces by atomic passivation

Pengfei Ou, Xiao Zhou, Cheng Chen

Black phosphorus (BP) is a semiconducting material with a direct finite band gap in its monolayer, attracting intense attention for its application in field-effect transistors. However, strong Fermi level pinning (FLP) has been observed for contacts betwee ...

2019

Alignment of energy levels in amorphous oxides and at semiconductor-water interfaces

Zhendong Guo

We conduct a detailed investigation of defects in two representative amorphous oxides: amorphous Al2O3 (am-Al2O3) and TiO2 (am-TiO2), by combining ab initio molecular dynamics (MD) simulations and hybrid functional calculations. Our results indicate that o ...

EPFL2019

Unveiling the electronic transformations in the semi-metallic correlated-electron transitional oxide Mo8O23

Marco Grioni, Gianmarco Gatti

Mo8O23 is a low-dimensional chemically robust transition metal oxide coming from a prospective family of functional materials, MoO3-x, ranging from a wide gap insulator (x = 0) to a metal (x = 1). The large number of stoichometric compounds with intermedia ...

Nature Research2019

Insights into the interfacial carrier behaviour of copper ferrite ( CuFe2O4) photoanodes for solar water oxidation

Kevin Sivula, Florian Le Formal, Nestor Guijarro Carratala, Liang Yao, Yongpeng Liu, Florent Alexandre Boudoire

Designing efficient yet robust photoanodes for water oxidation stands out as a major bottleneck in the realization of a feasible photoelectrochemical tandem cell for solar water splitting. Spinel copper ferrite (CuFe2O4) has been recently reported as a pot ...

Royal Society of Chemistry2019

Charge-carrier Dynamics in Metal Oxides and Hybrid Lead Perovskites investigated by Time-Resolved UV and X-ray Spectroscopy

Thomas Charles Henry Rossi

In modern ultrafast optoelectronic technologies based on wide band gap insulators, the non-equilibrium dynamics of photogenerated charges plays a major role. Unravelling the mechanisms of interaction between these charge carriers and their environment is c ...

EPFL2018

Novel Digital and Radio Frequency Electronic Functions Enabled by Steep-Slope Phase-Change Devices

Emanuele Andrea Casu

In the past half-century, the semiconductor industry has relied on the scaling of complementary metal-oxide-semiconductor (CMOS) transistor dimensions and on material and geometrical innovations to increase the computational density. Approaching the end of ...

EPFL2018

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

Hallmarks of Hunds coupling in the Mott insulator Ca2RuO4

Marco Grioni, Henrik Moodysson Rønnow, Simon Karl Moser, Johan Juul Chang, Claudia Giuseppina Fatuzzo, Gianmarco Gatti

A paradigmatic case of multi-band Mott physics including spin-orbit and Hund's coupling is realized in Ca2RuO4. Progress in understanding the nature of this Mott insulating phase has been impeded by the lack of knowledge about the low-energy electronic str ...

Nature Research2017

Bulk diffusive relaxation mechanisms in optically excited topological insulators

Helmuth Berger, Philippe Bugnon, Arnaud Magrez, Alberto Crepaldi

The possibility to inject spin currents in topological insulators (TIs) by ultrashort optical pulses has stimulated intense studies of their out-of-equilibrium electronic properties. However, a comprehensive description of the electronic relaxation dynamic ...

Amer Physical Soc2017

Evolution of the Fermi surface of BiTeCl with pressure

Helmuth Berger

We report measurements of Shubnikov-de Haas oscillations in the giant Rashba semiconductor BiTeCl under applied pressures up to similar to 2.5 GPa. We observe two distinct oscillation frequencies, corresponding to the Rashba-split inner and outer Fermi sur ...

Iop Publishing Ltd2017

Band structure diagram paths based on crystallography

Giovanni Pizzi

Systematic and automatic calculations of the electronic band structure are a crucial component of computationally-driven high-throughput materials screening. An algorithm, for any crystal, to derive a unique description of the crystal structure together wi ...

Elsevier2017

Synthesis and Physical Properties of 3d, 4d and 5d Transition Metal Compounds

Lin Yang

In this thesis I study the synthesis and basic physical properties characterization on 3

d

, 4

d

and 5

d

transition metal compounds. Great success has been obtained in 3

d

transition metal compounds, in which the electric states are well localized due t ...

EPFL2017

On the physics of multimode polaritons

Claudéric Ouellet-Plamondon

This thesis is devoted to the study of microcavity polariton systems, in which the strong coupling occurs between more than one exciton or photon modes i.e. multimode polaritons. The first part of this work states the theoretical background of light-matter ...

EPFL2017