One-dimensional edge states and superconductivity in few-layer WTe₂

Speaker: Artem Kononov (University of Basel, C. Schönenberger group)

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Title: One-dimensional edge states and superconductivity in few-layer WTe₂

Speaker: GHE Fellow A. Kononov (Univ. of Basel, C. Schönenberger group)

Date: December 15th 2020 @ 2pm

Place: Online zoom seminar

Abstract:

WTe₂ is a layered material with rich topological properties. As a bulk crystal it is a type-II Weyl semimetal and as a monolayer a two-dimensional topological insulator. Recently, it has been predicted that higher order topological insulator state can appear in WTe₂. An observation of 1D, highly conductive channels, known in this case as hinge states, is hindered by the bulk conductivity of WTe₂.

In this talk I will present some of our experimental results in transport in WTe₂. First, I will demonstrate a novel method to induce superconductivity in WTe₂ by placing it in contact with a normal metal palladium. Second, we employ the Josephson effect to disentangle the contribution of the hinge states from the bulk in electronic transport [1]. We observe 1D current carrying states on edges and steps in few-layer WTe₂. A supercurrent in them can be measured over distances up to 3 µm and in perpendicular magnetic field up to 2 T. Moreover, the dependence of the supercurrent with field is compatible with the asymmetric Josephson effect predicted to occur in topological systems with broken inversion symmetry.

[1] Nano Lett. 20, 6, 4228 (2020)