Publications related to Patterns and driving forces of dimensionality-dependent charge density waves in 2H-type transition metal dichalcogenides

Electronic structure and lattice dynamics of 1T-VSe2:Origin of the three-dimensional charge density wave

To characterize in detail the charge density wave (CDW) transition of 1T-VSe2, its electronic structure and lattice dynamics are comprehensively studied by means of x-ray diffraction, muon spectroscopy, angle resolved photoemission (ARPES), diffuse and ine ...

Amer Physical Soc2024

Hydrogen-induced tunable remanent polarization in a perovskite nickelate

Michele Kotiuga

Materials with field-tunable polarization are of broad interest to condensed matter sciences and solid-state device technologies. Here, using hydrogen (H) donor doping, we modify the room temperature metallic phase of a perovskite nickelate NdNiO3 into an ...

Nature Portfolio2024

Correlated insulator collapse due to quantum avalanche via in-gap ladder states

Xi Chen, Camille Didier Georges Aron

The significant discrepancy observed between the predicted and experimental switching fields in correlated insulators under a DC electric field far-from-equilibrium necessitates a reevaluation of current microscopic understanding. Here we show that an elec ...

Nature Portfolio2023

Layered metals as polarized transparent conductors

Philip Johannes Walter Moll, Matthias Carsten Putzke, Chunyu Guo, Maja Deborah Bachmann

The quest to improve transparent conductors balances two key goals: increasing electrical conductivity and increasing optical transparency. To improve both simultaneously is hindered by the physical limitation that good metals with high electrical conducti ...

Nature Portfolio2023

Modelling of metal alloys in realistic conditions with machine learning

Nataliya Lopanitsyna

Computer simulations based on statistical methods have emerged as a powerful tool for studying structure-property relationships at the atomistic level. However, to provide reliable insights into materials in realistic conditions, it is essential to accurat ...

EPFL2023

Machine-learning the electronic density of states: electronic properties without quantum mechanics

Chiheb Ben Mahmoud

The electronic density of states (DOS) quantifies the distribution of the energy levels that can be occupied by electrons in a quasiparticle picture and is central to modern electronic structure theory. It also underpins the computation and interpretation ...

EPFL2023

Charging and Electric Field Effects on Hydrogen Molecules Physisorbed on Graphene

Klaus Kern, Shai Mangel, Alessio Scavuzzo, Tobias Wollandt

Molecular hydrogen adsorbed on graphene was investigated by analyzing rotational excitation spectra obtained with a gate-tunable scanning tunneling microscope (STM). Through the shift of the rotational excitation energy, the tunability of physisorbed H2 on ...

AMER CHEMICAL SOC2023

Scrutinizing thermally stimulated current transients originating from trapped charges in organic semiconductors: A drift-diffusion study

Frank Nüesch, Beat Ruhstaller

Thermally stimulated current (TSC) is a widely used technique to assess trap states and extract their density, energy, and capture rate using analytical expressions. In many cases, the latter are derived from physical models pertaining to inorganic semicon ...

AIP Publishing2022

Nanoscale modelling of ionic transport in the porous C-S-H network

Khalil Ferjaoui

To reduce the CO2 footprint of construction materials, concrete producers blend their cement with Supplementary Cementitious Materials (SCMs). SCMs such as fly ash or blast furnace slag are mostly the byproducts of other industries. And while SCMs are chos ...

EPFL2022

Strengthening mechanisms in dilute and random solid solution high-entropy BCC alloys

Alireza Ghafarollahi

Tuning the mechanical properties of metals, including strength, through adjusting the type and/or concentration of added solute elements, has been recognized as an effective way to design and produce materials with desired or optimized mechanical propertie ...

EPFL2022

Topology, Oxidation States, and Charge Transport in Ionic Conductors

Federico Grasselli

Recent theoretical advances, based on a combination of concepts from Thouless' topological theory of adiabatic charge transport and a newly introduced gauge-invariance principle for transport coefficients, have permitted to connect (and reconcile) Faraday' ...

WILEY-V C H VERLAG GMBH2022

Disorder-induced electronic, magnetic, and optoelectronic properties of two-dimensional materials

Cheol Yeon Cheon

Technological advancement has been in cadence with material development by improving the purity of single crystals and, at the same time, controlling their imperfections. These capabilities have been especially vital for developing new technolo-gies based ...

EPFL2022

In situ nanoscale studies of copper-based catalysts for carbon dioxide electroreduction

Karla Banjac

The urgency of climate change demands the simultaneous removal of carbon dioxide from the atmosphere and the transition to renewable energy sources. This aim is realizable through electrochemical reduction of carbon dioxide (CO2RR), which is a promising ro ...

EPFL2021

Ab Initio Electron-Phonon Interactions in Correlated Electron Systems

Nicola Marzari, Matteo Cococcioni, Iurii Timrov, 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

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

Optimization of composition and structure of cemented carbide cutting tools

Samy Adjam

WC-Co cemented carbides are composites, which combine a hard phase consisting of WC grains and a metallic ductile phase as a binder. Their excellent mechanical properties, combining high hardness, toughness and refractory properties, make them excellent ma ...

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

Electrochemical reconstruction of ZnO for selective reduction of CO2 to CO

Andreas Züttel, Kun Zhao, Wen Luo, Emanuele Moioli, Jie Zhang, Qin Zhang

Electrocatalytic conversion of CO2 to valuable chemicals is a highly promising route to close the carbon cycle. Herein, Zn catalysts derived from electrochemical reconstruction of ZnO materials are presented as efficient CO2-to-CO catalysts. We found that ...

2020

Magnetic electron collimation in three-dimensional semi-metals

Xiangwei Huang, Philip Johannes Walter Moll, Jonas De Jesus Diaz Gomez, Matthias Carsten Putzke, Chunyu Guo

While electrons moving perpendicular to a magnetic field are confined to cyclotron orbits, they can move freely parallel to the field. This simple fact leads to complex current flow in clean, low carrier density semi-metals, such as long-ranged current jet ...

2020

Oxidation States, Thouless' Pumps, and Nontrivial Ionic Transport in Nonstoichiometric Electrolytes

Federico Grasselli

Thouless' quantization of adiabatic particle transport permits one to associate an integer topological charge with each atom of an electronically gapped material. If these charges are additive and independent of atomic positions, they provide a rigorous de ...

American Physical Society2020