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Oleg Yazyev

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Publications associées (153)

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

Multiple mobile excitons manifested as sidebands in quasi-one-dimensional metallic TaSe3

Oleg Yazyev, Christopher Marc Mudry, Daniel Gosalbez Martinez

Charge neutrality and their expected itinerant nature makes excitons potential transmitters of information. However, exciton mobility remains inaccessible to traditional optical experiments that only create and detect excitons with negligible momentum. Her ...

2022

Ab initio theory of magnetism in two-dimensional 1T-TaS2

Oleg Yazyev, Diego José Pasquier

We investigate, using a first-principles density functional methodology, the nature of magnetism in monolayer 1T phase of tantalum disulfide (1T-TaS2). Magnetism in the insulating phase of TaS2 is a longstanding puzzle and has led to a variety of theoretic ...

AMER PHYSICAL SOC2022

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

Charge ordering in Ir dimers in the ground state of Ba5AlIr2O11

Oleg Yazyev, Xingye Lu, Vamshi Mohan Katukuri, Thorsten Schmitt, Vladimir N. Strocov

It has been well established experimentally that the interplay of electronic correlations and spin-orbit interactions in Ir4+ and Ir5+ oxides results in insulating J(eff) = 1/2 and J(eff) = 0 ground states, respectively. However, in compounds where the str ...

AMER PHYSICAL SOC2022

Giant Chern number of a Weyl nodal surface without upper limit

Oleg Yazyev, Quansheng Wu, Shengnan Zhang

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

Intercalant-mediated Kitaev exchange in Ag3LiIr2O6

Oleg Yazyev, Ravi Yadav

The recently synthesized Ag3LiIr2O6 has been proposed as a Kitaev magnet in proximity to the quantum spin liquid phase. We explore its microscopic Hamiltonian and magnetic ground state using many-body quantum chemistry methods and exact diagonalization tec ...

AMER PHYSICAL SOC2022

Phase transition of layer-stacked borophene under pressure

Oleg Yazyev, Quansheng Wu, Xiao Dong

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

Unraveling the origin of the peculiar transition in the magnetically ordered phase of theWeyl semimetal Co3Sn2S2

Oleg Yazyev, Henrik Moodysson Rønnow, Ivica Zivkovic, Ravi Yadav, Jian Rui Soh

The recent discovery of topologically nontrivial behavior in Co3Sn2S2 stimulated a notable interest in this itinerant ferromagnet (T-C = 174 K). The exact magnetic state remains ambiguous, with several reports indicating the existence of a second transitio ...

AMER PHYSICAL SOC2022

Mott versus Hybridization Gap in the Low-Temperature Phase of 1T-TaS2

Oleg Yazyev, Diego José Pasquier

We address the long-standing problem of the ground state of 1T-TaS2 by computing the correlated electronic structure of stacked bilayers using the GW + EDMFT method. Depending on the surface termination, the semi-infinite uncorrelated system is either band ...

AMER PHYSICAL SOC2022

Spinor GW /Bethe-Salpeter calculations in BerkeleyGW: Implementation, symmetries, benchmarking, and performance

Oleg Yazyev, Manish Jain

Computing the GW quasiparticle band structure and Bethe-Salpeter equation (BSE) absorption spectra for materials with spin-orbit coupling have commonly been done by treating GW corrections and spin-orbit coupling (SOC) as separate perturbations to density- ...

AMER PHYSICAL SOC2022

Optically induced changes in the band structure of the Weyl charge-density-wave compound (TaSe4)(2)I

Helmuth Berger, Marco Grioni, Majed Chergui, Oleg Yazyev, Alberto Crepaldi, Daniel Gosalbez Martinez, Michele Puppin

Collective modes are responsible for the emergence of novel quantum phases in topological materials. In the quasi-one dimensional (1D) Weyl semimetal (TaSe4)(2)I < i , a charge density wave (CDW) opens band gaps at the Weyl points, thus turning the system ...

2022

Transport signatures of temperature-induced chemical potential shift and Lifshitz transition in layered type-II Weyl semimetal TaIrTe4

Oleg Yazyev, Quansheng Wu, Meng Yang

Temperature-induced Lifshitz transitions have been identified in several materials. Their chemical potential shows a substantial shift with changing temperature. The common feature of these materials is the coexistence of electron and hole pockets in the v ...

IOP PUBLISHING LTD2021

Quantum electronic transport across 'bite' defects in graphene nanoribbons

Oleg Yazyev, Michele Pizzochero, Kristians Cernevics

On-surface synthesis has recently emerged as an effective route towards the atomically precise fabrication of graphene nanoribbons (GNRs) of controlled topologies and widths. However, whether and to what degree structural disorder occurs in the resulting s ...

IOP PUBLISHING LTD2021

Temperature dependence of quantum oscillations from non-parabolic dispersions

Oleg Yazyev, Quansheng Wu, Amelia Emily-Kay Estry, Shengnan Zhang, Matthias Carsten Putzke, Chunyu Guo

A versatile methodology to detect topological quasiparticles by transport measurements remains an open problem. Here, the authors propose and experimentally observe the temperature dependence of the quantum oscillation frequency as a signature of non-trivi ...

Nature Portfolio2021

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

Origin of large magnetoresistance in the topological nonsymmorphic semimetal TaSe3

Jean-Philippe Ansermet, Helmuth Berger, Oleg Yazyev, Alberto Crepaldi, Gabriel Albert Autes, Gianmarco Gatti, Daniel Gosalbez Martinez, Quansheng Wu, Michele Puppin, Shengnan Zhang

TaSe3 is a layered van der Waals semimetal with several inverted band gaps throughout the entire Brillouin zone and nontrivial Z(2) topological indices, which place it at the boundary between a strong and a weak topological phase. Our transport experiments ...

2021

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

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

Hidden bulk and surface effects in the spin polarization of the nodal-line semimetal ZrSiTe

Helmuth Berger, Marco Grioni, Arnaud Magrez, Oleg Yazyev, Alberto Crepaldi, Mauro Fanciulli, Gianmarco Gatti, Daniel Gosalbez Martinez, Silvan Dino Marcos Roth

Local inversion symmetry breaking in centrosymmetric materials can lead to large spin polarization of the electronic band structure in separate sectors of the unit cell. Here, the authors reveal such hidden spin polarisation in ZrSiTe using spin and angle ...

NATURE RESEARCH2021

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