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Concept

Quantification de Landau

Publications associées (26)

Topological Effects in Carbon-based Two-dimensional Nanostructures

Yifei Guan

Recent advances on low-dimensional and topological materials has greatly inspired the research in condensed matter physics. This thesis is devoted to the computational and theoretical study of topological effects in two-dimensional materials, especially na ...

EPFL2023

Reentrant magic-angle phenomena in twisted bilayer graphene in integer magnetic fluxes

Oleg Yazyev, Yifei Guan

In this Letter we address the reentrance of magic-angle phenomena (band flatness and quantum-geometric transport) in twisted bilayer graphene (TBG) subjected to strong magnetic fluxes +/-(1)0, +/- 200, +/- 3(p0 ... ((D0 = h/e is the flux quantum per moire ...

AMER PHYSICAL SOC2022

Landau levels of the Euler class topology

Oleg Yazyev, Yifei Guan

Two-dimensional systems with C2T (PT) symmetry exhibit the Euler class topology E is an element of Z in each two-band subspace realizing a fragile topology beyond the symmetry indicators. By systematically studying the energy levels of Euler insulating pha ...

AMER PHYSICAL SOC2022

Anisotropic and nonlinear transport in microstructured 3D topological semimetals

Xiangwei Huang

Topological semimetals are frequently discussed as materials platforms for future electronics that exploit the remarkable properties of their quasiparticles. These ideas are mostly based on dispersion relations that mimic relativistic particles, such as We ...

EPFL2022

Landau Levels as a Probe for Band Topology in Graphene Moire Superlattices

Oleg Yazyev, Quansheng Wu, Yifei Guan

We propose Landau levels as a probe for the topological character of electronic bands in two-dimensional moire superlattices. We consider two configurations of twisted double bilayer graphene (TDBG) that have very similar band structures, but show differen ...

AMER PHYSICAL SOC2021

Non-linear Shubnikov-de Haas oscillations in the self-heating regime

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

We demonstrate a non-linear measurement scheme of the Shubnikov-de Haas effect based on Joule self-heating that builds on ideas of the 3 ?-method used in thin films. While the temperature dependence of the resistance, R(T), of clean metals at low temperatu ...

AIP Publishing2021

Extremely large magnetoresistance in the "ordinary" metal ReO3

Oleg Yazyev, Quansheng Wu, Shengnan Zhang

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

Determination of the Fermi surface and field-induced quasiparticle tunneling around the Dirac nodal loop in ZrSiS

Maarten Ruud van Delft

Unambiguous and complete determination of the Fermi surface is a primary step in understanding the electronic properties of topical metals and semimetals, but only in a relatively few cases has this goal been realized. In this work, we present a systematic ...

2020

Interacting Dirac materials

Gabriel Aeppli

We investigate the extent to which the class of Dirac materials in two-dimensions provides general statements about the behavior of both fermionic and bosonic Dirac quasiparticles in the interacting regime. For both quasiparticle types, we find common feat ...

2020

Tilted double Dirac cone and anisotropic quantum-spin-Hall topological insulator in mechanical granular graphene

Romain Christophe Rémy Fleury

Dirac degeneracies are essential ingredients to control topological charge exchanges between bands and trigger the unique edge transport properties of topological materials. In addition, when Dirac cones are tilted, exotic phenomena can emerge such as anom ...

2020

Linear and quadratic magnetoresistance in the semimetal SiP2

Oleg Yazyev, Quansheng Wu, Shengnan Zhang

Multiple mechanisms for extremely large magnetoresistance (XMR) found in many topologically nontrivial/trivial semimetals have been theoretically proposed, but experimentally it is unclear which mechanism is responsible in a particular sample. In this pape ...

AMER PHYSICAL SOC2020

Multi-frequency Shubnikov-de Haas oscillations in topological semimetal Pt2HgSe3

Marco Gibertini

Monolayer jacutingaite (Pt2HgSe3) has been recently identified as a candidate quantum spin Hall system with a 0.5 eV band gap, but no transport measurements have been performed so far on this material, neither in monolayer nor in the bulk. By using a dedic ...

IOP PUBLISHING LTD2020

Spin-Split Band Hybridization in Graphene Proximitized with alpha-RuCl3 Nanosheets

Klaus Kern, Marko Burghard

Proximity effects induced in the two-dimensional Dirac material graphene potentially open access to novel and intriguing physical phenomena. Thus far, the coupling between graphene and ferromagnetic insulators has been experimentally established. However, ...

AMER CHEMICAL SOC2019

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

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

Experimental determination of Rashba and Dresselhaus parameters and g*- factor anisotropy via Shubnikov-de Haas oscillations

Dirk Grundler

The spin splitting of conduction band electrons in inversion-asymmetric InGaAs/InP quantum wells (QWs) is studied by Shubnikov-de Haas measurements combining the analysis of beating patterns and coincidence measurements in doubly tilted magnetic fields. Th ...

Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft2017

Surface States Transport in Topological Insulator Bi0.83Sb0.17 Nanowires

Jean-Philippe Ansermet

We investigate the transport properties of topological insulator (TI) nanowires. Single-crystal nanowire samples with diameters ranging from 75 nm to 1.1 m are prepared using high frequency liquid phase casting in a glass capillary; cylindrical single crys ...

Springer Verlag2016

Quantum properties of charged ferroelectric domain walls

Nava Setter, Alexander Tagantsev

We consider the properties of charged domain walls in ferroelectrics as a quantum problem. This includes determination of self-consistent attracting 1D potential for compensating charge carriers, the number and positions of discrete energy levels in this p ...

Amer Physical Soc2015

Unusual Shubnikov-de Haas oscillations in BiTeCl

Helmuth Berger, Arnaud Magrez, Philippe Bugnon

We report measurements of Shubnikov-de Haas oscillations in single crystals of BiTeCl at magnetic fields up to 31 T and at temperatures as low as 0.4 K. Two oscillation frequencies were resolved at the lowest temperatures, F-1 = 65 +/- 4 T and F-2 = 156 +/ ...

Amer Physical Soc2014

Pressure tuning the Fermi level through the Dirac point of giant Rashba semiconductor BiTeI

Helmuth Berger

We report measurements of Shubnikov-de Haas oscillations in the giant Rashba semiconductor BiTeI under applied pressures up to similar to 2GPa. We observe one high frequency oscillation at all pressures and one low frequency oscillation that emerges betwee ...

Iop Publishing Ltd2014