Quansheng Wu

László Forró, Helmuth Berger, Oleg Yazyev, Christoph Koch, Quansheng Wu, Philip Johannes Walter Moll, Matthias Carsten Putzke, Edoardo Martino, Shengnan Zhang, Konstantin Semeniuk

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

Unidirectional Kondo scattering in layered NbS2

Crystalline defects can modify quantum interactions in solids, causing unintuitive, even favourable, properties such as quantum Hall effect or superconducting vortex pinning. Here we present another example of this notion-an unexpected unidirectional Kondo ...

NATURE PORTFOLIO2021

Moire Flat Bands in Twisted Double Bilayer Graphene

Oleg Yazyev, Quansheng Wu, Seyedeh Fatemeh Haddadi Givi

We investigate twisted double bilayer graphene (TDBG), a four-layer system composed of two AB-stacked graphene bilayers rotated with respect to each other by a small angle. Our ab initio band structure calculations reveal a considerable energy gap at the c ...

AMER CHEMICAL SOC2020

Topological phase transitions driven by strain in monolayer tellurium

Oleg Yazyev, Quansheng Wu, Wei Zhang

Two-dimensional (2D) Xenes of a single type of element can offer fascinating electronic properties, such as massless Dirac fermions for extremely high charge-carrier mobility and topological insulators for dissipationless electron transport. However, the r ...

AMER PHYSICAL SOC2018

Correlated states in twisted double bilayer graphene

Oleg Yazyev, Quansheng Wu, Na Li

Electron-electron interactions play an important role in graphene and related systems and can induce exotic quantum states, especially in a stacked bilayer with a small twist angle(1-7). For bilayer graphene where the two layers are twisted by the 'magic a ...

NATURE PUBLISHING GROUP2020

Large magnetoresistance and nonzero Berry phase in the nodal-line semimetal MoO2

We performed calculations of the electronic band structure and the Fermi surface as well as measured the longitudinal resistivity rho(xx)(T,H), Hall resistivity rho(xy)(T,H), and quantum oscillations of the magnetization as a function of temperature at var ...

2020

Crystal Field Effect and Electric Field Screening in Multilayer Graphene with and without Twist

We address the intrinsic polarization and screening of an external electric field in a broad range of ordered and twisted configurations of multilayer graphene, using an ab initio approach combining density functional theory and the Wannier function formal ...

AMER CHEMICAL SOC2021

Magnetoresistance from Fermi surface topology

Oleg Yazyev, Quansheng Wu, Shengnan Zhang, Yizhu Liu

Extremely large nonsaturating magnetoresistance has recently been reported for a large number of both topologically trivial and nontrivial materials. Different mechanisms have been proposed to explain the observed magnetotransport properties, yet without a ...

2019

Observation of a singular Weyl point surrounded by charged nodal walls in PtGa

Oleg Yazyev, Jan Hugo Dil, Quansheng Wu, Shengnan Zhang

Constrained by the Nielsen-Ninomiya no-go theorem, in all so-far experimentally determined Weyl semimetals (WSMs) the Weyl points (WPs) always appear in pairs in the momentum space with no exception. As a consequence, Fermi arcs occur on surfaces which con ...

Nature Research2021

Giant Chern number of a Weyl nodal surface without upper limit

Weyl nodes can be classified into zero-dimensional (0D) Weyl points, 1D Weyl nodal lines, and 2D Weyl nodal surfaces (WNS), which possess finite Chern numbers. Up to date, the largest Chern number of WPs identified in Weyl semimetals is 4, which is thought ...

AMER PHYSICAL SOC2022

Automated construction of symmetrized Wannier-like tight-binding models from ab initio calculations

Wannier tight-binding models are effective models constructed from first-principles calculations. As such, they bridge a gap between the accuracy of first-principles calculations and the computational simplicity of effective models. In this work, we extend ...

AMER PHYSICAL SOC2018

Irvsp: To obtain irreducible representations of electronic states in the VASP

We present an open-source program irvsp, to compute irreducible representations of electronic states for all 230 space groups with an interface to the Vienna ab-initio Simulation Package. This code is fed with plane-wave-based wavefunctions (e.g. WAVECAR) ...

ELSEVIER2021

The 2021 quantum materials roadmap

In recent years, the notion of 'Quantum Materials' has emerged as a powerful unifying concept across diverse fields of science and engineering, from condensed-matter and coldatom physics to materials science and quantum computing. Beyond traditional quantu ...

IOP PUBLISHING LTD2020

Topological phonons and thermoelectricity in triple-point metals

Joël Mesot, Oleg Yazyev, Quansheng Wu, Gabriel Albert Autes

Recently published discoveries of acoustic- and optical-mode inversion in the phonon spectrum of certain metals became the first realistic example of noninteracting topological bosonic excitations in existing materials. However, the observable physical and ...

AMER PHYSICAL SOC2018

Observation of Weyl Nodes in Robust Type-II Weyl Semimetal WP2

Distinct to type-I Weyl semimetals (WSMs) that host quasiparticles described by the Weyl equation, the energy dispersion of quasiparticles in type-II WSMs violates Lorentz invariance and the Weyl cones in the momentum space are tilted. Since it was propose ...

AMER PHYSICAL SOC2019

Phase transition of layer-stacked borophene under pressure

The 8-Pmmn borophene, a boron analog of graphene, hosts tilted and anisotropic massless Dirac fermion quasiparticles owing to the presence of a distorted graphenelike sublattice. First-principles calculations show that stacked 8-Pmmn borophene is transform ...

AMER PHYSICAL SOC2022

Non-Abelian band topology in noninteracting metals

Electron energy bands of crystalline solids generically exhibit degeneracies called band-structure nodes. Here, we introduce non-Abelian topological charges that characterize line nodes inside the momentum space of crystalline metals with space-time invers ...

American Association for the Advancement of Science2019

Linear and quadratic magnetoresistance in the semimetal SiP2

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

Non-Abelian reciprocal braiding of Weyl points and its manifestation in ZrTe