Gate-induced superconductivity in a monolayer topological insulator.

Sajadi, Ebrahim; Palomaki, Tauno; Fei, Zaiyao; Zhao, Wenjin; Bement, Philip; Olsen, Christian; Luescher, Silvia; Xu, Xiaodong et al. · Science · 2018

basic_science · Level V

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Abstract

The layered semimetal tungsten ditelluride (WTe<sub>2</sub>) has recently been found to be a two-dimensional topological insulator (2D TI) when thinned down to a single monolayer, with conducting helical edge channels. We found that intrinsic superconductivity can be induced in this monolayer 2D TI by mild electrostatic doping at temperatures below 1 kelvin. The 2D TI-superconductor transition can be driven by applying a small gate voltage. This discovery offers possibilities for gate-controlled devices combining superconductivity and nontrivial topological properties, and could provide a basis for quantum information schemes based on topological protection.