Gate-tunable negative longitudinal magnetoresistance in the predicted type-II Weyl semimetal WTe2

Wang, Yaojia; Liu, Erfu; Liu, Huimei; Pan, Yiming; Zhang, Longqiang; Zeng, Junwen; Fu, Yajun; Wang, Miao; Xu, Kang; Huang, Zhongbing; Wang, Zhenlin; Lu, Hai-Zhou; Xing, D. Y.; Wang, Baigeng; Wan, Xiangang; Miao, Feng

doi:10.1038/ncomms13142

Cited by 252 publications

(205 citation statements)

References 53 publications

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“…Bulk WTe 2 is predicted to be a type-II Weyl semimetal [13], in which Lorenz invariance is absent and the Weyl point appears at the boundary of electron and hole pockets [13,14]. This prediction has triggered renewed interest in this material [15][16][17][18][19][20]. In the monolayer limit, WTe 2 is predicted to be a topological semimetal in which both topological metallic edge states and 2D metallic bulk states are present [21].…”

Section: Introductionmentioning

confidence: 99%

Thickness-dependent electronic structure in WTe2 thin films

Xiang

Srinivasan

et al. 2018

Phys. Rev. B

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X. (2018). Thickness-dependent electronic structure in WTe2 thin films. Physical Review B: Covering condensed matter and materials physics, 98 (3), 035115-1-035115-10. Thickness-dependent electronic structure in WTe2 thin films AbstractWe study the electronic structure of WTe2 thin films with different thicknesses. High-quality thin-film samples are obtained with carrier mobility up to 5000 cm2 V−1 s−1, which enables us to resolve the four main Fermi pockets from Shubnikov-de Haas (SdH) oscillations. Angle-resolved SdH oscillations show that the WTe2 thin films cross from three-dimensional to two-dimensional electronic systems at a thickness of ∼ 20 nm. Using the field effect, the nature of the Fermi pockets in thin-film WTe2 is identified, and the evolution of SdH oscillation frequencies is traced over different sample thicknesses. It is found that the frequencies dramatically decrease at a thickness of approximately 12 nm, which indicates the onset of finite-size effects on the band structure. Our work pins down two critical length scales of the thickness-dependent electronic structure in WTe2 thin films. Disciplines Engineering | Physical Sciences and Mathematics Publication DetailsXiang, F., Srinivasan, A., Du, Z. Z., Klochan, O., Dou, S., Hamilton, A. We study the electronic structure of WTe 2 thin films with different thicknesses. High-quality thin-film samples are obtained with carrier mobility up to 5000 cm 2 V −1 s −1 , which enables us to resolve the four main Fermi pockets from Shubnikov-de Haas (SdH) oscillations. Angle-resolved SdH oscillations show that the WTe 2 thin films cross from three-dimensional to two-dimensional electronic systems at a thickness of ∼ 20 nm. Using the field effect, the nature of the Fermi pockets in thin-film WTe 2 is identified, and the evolution of SdH oscillation frequencies is traced over different sample thicknesses. It is found that the frequencies dramatically decrease at a thickness of approximately 12 nm, which indicates the onset of finite-size effects on the band structure. Our work pins down two critical length scales of the thickness-dependent electronic structure in WTe 2 thin films.

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Section: Introductionmentioning

confidence: 99%

Thickness-dependent electronic structure in WTe2 thin films

Xiang

Srinivasan

et al. 2018

Phys. Rev. B

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“…Many unique transport characteristics have been predicted for the Weyl band structures in general and the Fermi arc states in particular. [44][45][46][47][48][49][50][51] Transport experiments on Weyl semimetals have indeed seen several intriguing features; 17,[52][53][54][55][56][57][58][59][60] however, the link to the Weyl band structure is often difficult to make. To clarify this connection, it would be ideal to use a system where Weyl behavior can be switched on and off using an experimentally tunable parameter like temperature, pressure or applied field.…”

Section: Introductionmentioning

confidence: 99%

Temperature-driven topological transition in 1T'-MoTe2

et al. 2018

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The topology of Weyl semimetals requires the existence of unique surface states. Surface states have been visualized in spectroscopy measurements, but their connection to the topological character of the material remains largely unexplored. 1T'-MoTe 2 , presents a unique opportunity to study this connection. This material undergoes a phase transition at 240 K that changes the structure from orthorhombic (putative Weyl semimetal) to monoclinic (trivial metal), while largely maintaining its bulk electronic structure. Here, we show from temperature-dependent quasiparticle interference measurements that this structural transition also acts as a topological switch for surface states in 1T'-MoTe 2 . At low temperature, we observe strong quasiparticle scattering, consistent with theoretical predictions and photoemission measurements for the surface states in this material. In contrast, measurements performed at room temperature show the complete absence of the scattering wavevectors associated with the trivial surface states. These distinct quasiparticle scattering behaviors show that 1T'-MoTe 2 is ideal for separating topological and trivial electronic phenomena via temperature-dependent measurements.

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“…For example, the Majorana-like excitations are detected in superconducting heterostructures [3][4][5][6]; the Dirac [7][8][9][10][11][12] and Weyl [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] fermions are observed in some compounds. These quasiparticles in solid states are not only important for basic science, but also show great potential for practical applications on new devices [30,31].Because symmetries in condensed matter physics are usually much lower than the Poincaré symmetry in high energy physics, quasiparticles in solid states are less constrained such that various new types of fermionic excitations are predicted to exist in 3D lattices [32]. Among these allowed by space group (SG) symmetries are spin-1 and spin-3/2 massless fermionic excitations, besides the well-known spin-1/2 case, namely the Weyl fermion.…”

mentioning

confidence: 99%

Multiple Types of Topological Fermions in Transition Metal Silicides

Tang¹,

Zhou²,

Zhang³

2017

Phys. Rev. Lett.

418

432

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Exotic massless fermionic excitations with non-zero Berry flux, other than Dirac and Weyl fermions, could exist in condensed matter systems under the protection of crystalline symmetries, such as spin-1 excitations with 3-fold degeneracy and spin-3/2 Rarita-Schwinger-Weyl fermions. Herein, by using ab initio density functional theory, we show that these unconventional quasiparticles coexist with type-I and type-II Weyl fermions in a family of transition metal silicides, including CoSi, RhSi, RhGe and CoGe, when the spin-orbit coupling (SOC) is considered. Their non-trivial topology results in a series of extensive Fermi arcs connecting projections of these bulk excitations on side surface, which is confirmed by (010) surface electronic spectra of CoSi. In addition, these stable arc states exist within a wide energy window around the Fermi level, which makes them readily accessible in angle-resolved photoemission spectroscopy measurements.Introduction.-Three types of fermions play fundamental roles in our understanding of nature: Majorana, Dirac and Weyl [1]. Much attention has been paid to looking for these fundamental particles in high energy physics during past few decades, whereas only signature of Dirac fermions is captured. Interestingly, the same movement comes up in the field of condensed matter physics [2], and great achievements have been made in last few years. For example, the Majorana-like excitations are detected in superconducting heterostructures [3][4][5][6]; the Dirac [7][8][9][10][11][12] and Weyl [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] fermions are observed in some compounds. These quasiparticles in solid states are not only important for basic science, but also show great potential for practical applications on new devices [30,31].Because symmetries in condensed matter physics are usually much lower than the Poincaré symmetry in high energy physics, quasiparticles in solid states are less constrained such that various new types of fermionic excitations are predicted to exist in 3D lattices [32]. Among these allowed by space group (SG) symmetries are spin-1 and spin-3/2 massless fermionic excitations, besides the well-known spin-1/2 case, namely the Weyl fermion. All of these massless quasiparticles can be described by the low energy Hamiltonian in a unified manner to the linear order of momentum

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Gate-tunable negative longitudinal magnetoresistance in the predicted type-II Weyl semimetal WTe2

Cited by 252 publications

References 53 publications

Thickness-dependent electronic structure in WTe2 thin films

Thickness-dependent electronic structure in WTe2 thin films

Temperature-driven topological transition in 1T'-MoTe2

Multiple Types of Topological Fermions in Transition Metal Silicides

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