Quasiparticle interference of the Fermi arcs and surface-bulk connectivity of a Weyl semimetal

Inoue, Hiroyuki; Gyenis, András; Wang, Zhijun; Li, Jian; W., Oh, Seong; Jiang, Shan; Ni, Ni; Bernevig, B. Andrei; Yazdani, Ali

doi:10.1126/science.aad8766

Cited by 190 publications

(213 citation statements)

References 40 publications

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“…5,41 Accordingly, most spectroscopic experiments have concentrated on observing the surface states in these materials. The majority of these experiments have focused on type I Weyl semimetals, [13][14][15][16][18][19][20][21][22][23][24][25][26][27]34,42 with a smaller number of observations on type-II Weyl semimetals including MoTe 2 30-32,35,36,40 and its alloys with WTe 2.…”

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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Section: Introductionmentioning

confidence: 99%

Temperature-driven topological transition in 1T'-MoTe2

et al. 2018

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“…[10][11][12][13][14] The Weyl semimetal normally exhibits a giant and sometime negative magnetoresistance (MR) due to the semimetal behavior and the opposite spin chirality of the paired Weyl nodes. [15][16][17][18] It is very interesting and highly desired to realize bulk superconductivity in such Weyl semimetals.…”

Section: Introductionmentioning

confidence: 99%

Concurrence of superconductivity and structure transition in Weyl semimetal TaP under pressure

Zhou

Guo

et al. 2017

npj Quant Mater

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Weyl semimetal defines a material with three-dimensional Dirac cones, which appear in pair due to the breaking of spatial inversion or time reversal symmetry. Superconductivity is the state of quantum condensation of paired electrons. Turning a Weyl semimetal into superconducting state is very important in having some unprecedented discoveries. In this work, by doing resistive measurements on a recently recognized Weyl semimetal TaP under pressures up to about 100 GPa, we show the concurrence of superconductivity and a structure transition at about 70 GPa. It is found that the superconductivity becomes more pronounced when decreasing pressure and retains when the pressure is completely released. High-pressure x-ray diffraction measurements also confirm the structure phase transition from I4 1 md to P-6m2 at about 70 GPa. More importantly, ab-initial calculations reveal that the P-6m2 phase is a new Weyl semimetal phase and has only one set of Weyl points at the same energy level. Our discovery of superconductivity in TaP by high pressure will stimulate investigations on superconductivity and Majorana fermions in Weyl semimetals.

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“…STS measurments have been performed on several TWS materials, such as TaAs [34][35][36], On the theoretical side, we performed electronic structure calculations using DFT as implemented in the Vienna Ab Initio simulation package (VASP) [40] with projector augmented wave basis sets [41] that included spin-orbit coupling. The PBE functional [42] was used in the exchange-correlation potential.…”

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confidence: 99%

Quasiparticle interference of surface states in the type-II Weyl semimetal WTe2

Zhang

et al. 2017

Phys. Rev. B

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Topological Weyl semimetal (TWS) is a metal, where low energy excitations behave like Weyl fermions of high-energy physics. It was recently shown that due to the lower symmetry of condensed matter systems, they can realize two distinct types of Weyl fermions. The type-I Weyl fermion in a metal is formed by a linear crossing of two bands at a point in the crystalline momentum space -Brillouin zone (BZ). The second type TWSs host type-II Weyl points appearing at the touching points of electron and hole pockets, which is a result of tilted linear dispersion. The type-II TWS was predicted to exist in several compounds, including WTe 2 . Several ARPES studies of WTe 2 were reported so far, having contradictory conclusions on the topological nature of observed Fermi arcs. In this work, we report the results of spectroscopic imaging with a scanning tunneling microscope and first principle calculations, establishing clear quasiparticle interference features of the surface states of WTe 2 . Our work provides a strong evidence for surface state scattering.Although the surface Fermi arcs are clearly observed, it is still difficult to prove the existence of predicted Type-II Weyl points in the bulk.

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Quasiparticle interference of the Fermi arcs and surface-bulk connectivity of a Weyl semimetal

Cited by 190 publications

References 40 publications

Temperature-driven topological transition in 1T'-MoTe2

Temperature-driven topological transition in 1T'-MoTe2

Concurrence of superconductivity and structure transition in Weyl semimetal TaP under pressure

Quasiparticle interference of surface states in the type-II Weyl semimetal WTe2

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