Room-temperature quantum spin Hall phase in laser-patterned few-layer 1T′- MoS2

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, ~e2/2 h and e2/4 h, 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 ; The work carried out at Aoyama Gakuin University was partly supported by a grant for private universities and a Grant-in-Aid for Scientific Research (JP15K13277) awarded by MEXT. The work at the University of Tokyo was partly supported by Grant-in-Aid for Scientific Research (JP17K05492, JP18H04218, and JP19H00652). J.J.P. and S.P. acknowledge Spanish MINECO through Grant FIS2016-80434-P, PID2019-109539GB-C43, the Fundación Ramón Areces, the María de Maeztu Program for Units of Excellence in R&D (CEX2018-000805), the Comunidad Autónoma de Madrid through Grant No. S2018/NMT-4321 (nanomagCOST-CM), and the European Union Seventh Framework Programme under Graphene Flagship Grant No. 604391. S.P. was also supported by the VILLUM FONDEN via the Centre of Excellence for Dirac Materials (Grant No. 11744) and acknowledges the computer resources and assistance provided by the Centro de Computación Científica of the Universidad Autónoma de Madrid and computer resources at ...