Discovery of a new type of topological Weyl fermion semimetal state in MoxW1−xTe2

Abstract

The recent discovery of a Weyl semimetal in TaAs offers the first Weyl fermion observed in nature and dramatically broadens the classification of topological phases. However, in TaAs it has proven challenging to study the rich transport phenomena arising from emergent Weyl fermions. The series MoxW1−xTe2 are inversion-breaking, layered, tunable semimetals already under study as a promising platform for new electronics and recently proposed to host Type II, or strongly Lorentz-violating, Weyl fermions. Here we report the discovery of a Weyl semimetal in MoxW1−xTe2 at x=25%. We use pump-probe angle-resolved photoemission spectroscopy (pump-probe ARPES) to directly observe a topological Fermi arc above the Fermi level, demonstrating a Weyl semimetal. The excellent agreement with calculation suggests that MoxW1−xTe2 is a Type II Weyl semimetal. We also find that certain Weyl points are at the Fermi level, making MoxW1−xTe2 a promising platform for transport and optics experiments on Weyl semimetals.

The study on quantum material WTe2

“…I. Belopolski et al [73] demonstrated in Mo x W 1-x Te 2 that a group of WPs were at the Fermi level as shown in Figure 5, making Mo x W 1-x Te 2 a promising platform for transport and optics experiments on Weyl semi-metals. H. Zheng et al [74] visualized the interference pattern on Mo 0.66 W 0.34 Te 2 by atomic resolution scanning tunnelling microscopy and spectroscopy (STM-STS).…”

Berry curvature dipole in Weyl semimetal materials: An ab initio study

“…For example, both the carrier doping and external pressure are known to engineer the Fermi surface of these compounds (e.g., Refs. 10,44,[48][49][50].…”

Magnetic and noncentrosymmetric Weyl fermion semimetals in the RAlGe family of compounds ( R=rareearthChang1, Singh2, Xu3 et al. 2018Phys. Rev. BSelf Cite17631020View full textAdd to dashboardCite

“…Further transport measurements have revealed unconventional magnetic and optical responses of TaAs family [26][27][28][29]. Despite recent advances of topological semimetals in both theory [30][31][32][33][34][35][36][37][38][39][40][41][42][43] and experiment [26][27][28][29][44][45][46][47][48][49][50][51] , the ferromagnetic Weyl semimetal [8,9,[52][53][54][55][56][57] has not been realised in experiments. A key issue is that first-principles band structure calculations on these magnetic materials (e.g.…”