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
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 . 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.
 Nano Lett. 20, 6, 4228 (2020)