Observation of the quantum spin Hall effect up to 100 kelvin in a monolayer crystal

Sanfeng Wu; Valla Fatemi; Quinn D Gibson; Kenji Watanabe; Takashi Taniguchi; Robert J Cava; Pablo Jarillo-Herrero

doi:10.1126/science.aan6003

Observation of the quantum spin Hall effect up to 100 kelvin in a monolayer crystal

Science. 2018 Jan 5;359(6371):76-79. doi: 10.1126/science.aan6003.

Authors

Sanfeng Wu¹, Valla Fatemi¹, Quinn D Gibson², Kenji Watanabe³, Takashi Taniguchi³, Robert J Cava², Pablo Jarillo-Herrero⁴

Affiliations

¹ Department of Physics, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA. swu02@mit.edu vfatemi@mit.edu pjarillo@mit.edu.
² Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
³ Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
⁴ Department of Physics, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.

PMID: 29302010
DOI: 10.1126/science.aan6003

Abstract

A variety of monolayer crystals have been proposed to be two-dimensional topological insulators exhibiting the quantum spin Hall effect (QSHE), possibly even at high temperatures. Here we report the observation of the QSHE in monolayer tungsten ditelluride (WTe₂) at temperatures up to 100 kelvin. In the short-edge limit, the monolayer exhibits the hallmark transport conductance, ~e²/h per edge, where e is the electron charge and h is Planck's constant. Moreover, a magnetic field suppresses the conductance, and the observed Zeeman-type gap indicates the existence of a Kramers degenerate point and the importance of time-reversal symmetry for protection from elastic backscattering. Our results establish the QSHE at temperatures much higher than in semiconductor heterostructures and allow for exploring topological phases in atomically thin crystals.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't