Large quantum-spin-Hall gap in single-layer 1T' WSe₂.

ABSTRACT: Two-dimensional (2D) topological insulators (TIs) are promising platforms for low-dissipation spintronic devices based on the quantum-spin-Hall (QSH) effect, but experimental realization of such systems with a large band gap suitable for room-temperature applications has proven difficult. Here, we report the successful growth on bilayer graphene of a quasi-freestanding WSe₂ single layer with the 1T' structure that does not exist in the bulk form of WSe₂. Using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy/spectroscopy (STM/STS), we observe a gap of 129 meV in the 1T' layer and an in-gap edge state located near the layer boundary. The system's 2D TI characters are confirmed by first-principles calculations. The observed gap diminis

SUBMITTER: Chen P 

PROVIDER: S-EPMC5962594 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature