Discovery of a new type of topological Weyl fermion semimetal state in Mo${}_x$W${}_{1-x}$Te${}_2$

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 Mo${}_x$W${}_{1-x}$Te${}_2$ 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 Mo${}_x$W${}_{1-x}$Te${}_2$ 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 Mo${}_x$W${}_{1-x}$Te${}_2$ is the first Type II Weyl semimetal. We also find that certain Weyl points are at the Fermi level, making Mo${}_x$W${}_{1-x}$Te${}_2$ a promising platform for transport and optics experiments on Weyl semimetals.

References in corpus (8)

• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Phase transition between the quantum spin Hall and insulator phases in 3D: emergence of a topological gapless phase
• Gate-Tunable Negative Longitudinal Magnetoresistance in the Predicted Type-II Weyl Semimetal WTe2
• Consequences of a condensed matter realization of Lorentz violating QED in Weyl semi-metals
• Quantum transport in Dirac materials: signatures of tilted and anisotropic Dirac and Weyl cones
• Topology and Interactions in a Frustrated Slab: Tuning from Weyl Semimetals to C > 1 Fractional Chern Insulators
• Time-resolved photoemission apparatus achieving sub-20-meV energy resolution and high stability

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