摘要
Monolayer transition metal dichalcogenides(TMDCs) with the 1 T0 structure are a new class of large-gap two-dimensional(2 D) topological insulators, hosting topologically protected conduction channels on the edges. However, the 1 T0 phase is metastable compared to the 2 H phase for most of 2 D TMDCs, among which the 1 T0 phase is least favored in monolayer MoS2. Here we report a clean and controllable technique to locally induce nanometer-sized 1 T0 phase in monolayer 2 H-MoS2 via a weak Argon-plasma treatment,resulting in topological phase boundaries of high density. We found that the stabilization of 1 T0 phase arises from the concerted effects of S vacancies and the tensile strain. Scanning tunneling spectroscopy(STS) clearly reveals a spin-orbit band gap(~60 meV) and topologically protected in-gap states residing at the 1 T0-2 H phase boundary, which are corroborated by density-functional theory(DFT) calculations.The strategy developed in this work can be generalized to a large variety of TMDCs materials, with potentials to realize scalable electronics and spintronics with low dissipation.
Monolayer transition metal dichalcogenides（TMDCs） with the 1 T0 structure are a new class of large-gap two-dimensional（2 D） topological insulators, hosting topologically protected conduction channels on the edges. However, the 1 T0 phase is metastable compared to the 2 H phase for most of 2 D TMDCs, among which the 1 T0 phase is least favored in monolayer MoS2. Here we report a clean and controllable technique to locally induce nanometer-sized 1 T0 phase in monolayer 2 H-MoS2 via a weak Argon-plasma treatment,resulting in topological phase boundaries of high density. We found that the stabilization of 1 T0 phase arises from the concerted effects of S vacancies and the tensile strain. Scanning tunneling spectroscopy（STS） clearly reveals a spin-orbit band gap（～60 meV） and topologically protected in-gap states residing at the 1 T0-2 H phase boundary, which are corroborated by density-functional theory（DFT） calculations.The strategy developed in this work can be generalized to a large variety of TMDCs materials, with potentials to realize scalable electronics and spintronics with low dissipation.
基金
financially supported by the National Natural Science Foundation of China (11888101, 11634001, 11834017 and 61888102)
the National Key R&D Program (2016YFA0300901 and 2017YFA0205003)
the Strategic Priority Research Program of Chinese Academy of Sciences (XDB28000000 and XDB30000000)
Beijing Municipal Science & Technology Commission
support from National Science Fund for Distinguished Young Scholars (21725302)
Cheung Kong Young Scholar Program
