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Anisotropic Edge-enhanced Transport in WTe2 Josephson Junction

Speaker:Prof. Gil-Ho Lee
Affiliation:Department of Physics, Pohang University of Science and Technology
Date:June 20, 2019 (Thursday)
Time:4:00 p.m.
Venue:Room 522, 5/F, Chong Yuet Ming Physics Building, HKU


Type-II Weyl semimetal was proposed as a new kind of topological material, where highly tilted Weyl cones appear in momentum space with Lorentz invariance violation. Despite the motivation of understanding its exotic physical properties, the observation of topological states emerging at surface has been largely hindered by trivial bulk conductions. Here, we present spatially-resolved measurements on topological edge states of few-layer WTe2 by employing magnetic field interference of Josephson coupling. We find that the Josephson current flowing along a-axis of WTe2 has enhancements at device edges. However, Josephson current along b-axis flows in a uniform distribution without enhancement at device edges. Our experimental observation in combination with theoretical calculation provides evidence for the anisotropic topological edge states inherited from quantum spin Hall edge states of monolayer WTe2. Our study establishes WTe2 as an intriguing platform for studying novel phase of matter with combining topological materials and superconductivity.

Coffee and tea will be served 20 minutes prior to the seminar.

Anyone interested is welcome to attend.