Room-temperature quantum spin Hall phase in laser-patterned few-layer 1T'- MoS2

TL;DR

This paper demonstrates the realization of a room-temperature quantum spin Hall phase in laser-patterned few-layer 1T'-MoS2, supported by resistance measurements and theoretical calculations, paving the way for topological devices.

Contribution

It reports the first observation of room-temperature QSH phase in laser-patterned 1T'-MoS2, overcoming previous uniformity and defect challenges.

Findings

Hallmark conductance values (~e2/2h and e2/4h) observed

Magnetic-field dependence supports QSH phase

Laser patterning enables room-temperature topological states

Abstract

The quantum-spin-Hall (QSH) phase of 2D topological insulators has attracted increased attention since the onset of 2D materials research. While large bulk gaps with vanishing edge gaps in atomically thin layers have been reported, verifications of the QSH phase by resistance measurements are comparatively few. This is partly due to the poor uniformity of the bulk gap induced by the substrate over a large sample area and/or defects induced by oxidation. Here, we report the observation of the QSH phase at room-temperature in the 1T'-phase of few-layer MoS2 patterned onto the 2H semiconducting phase using low-power and short-time laser beam irradiation. Two different resistance measurements reveal hallmark transport conductance values, ~e2/2h and e2/4h, as predicted by the theory. Magnetic-field dependence, scanning tunneling spectra, and calculations support the emergence of the room-temperature QSH phase. Although further experimental verification is still desirable, our results provide feasible application to room-temperature topological devices.