Searching for new quantum spin Hall insulators with large fully opened energy gap to overcome the thermal disturbance at room temperature has attracted tremendous attention due to the one-dimensional (1D) spin-momentum locked topological edge states serving as dissipationless channels for the practical applications in low consumption electronics and high performance spintronics. Here, we report the investigation of topological nature of monolayer Bi4Br4 by the techniques of scanning tunneling microscopy and angle-resolved photoemission spectroscopy (ARPES). The topological non-triviality of 1D edge state integrals within the large bulk energy gap (~ 0.2 eV) is revealed by the first-principle calculations. The ARPES measurements at different temperature show a temperature-induced Lifshitz transition, corresponding to the resistivity anomaly caused by the shift of chemical potential. The connection between the emergency of superconductivity and the Lifshitz transition is discussed.
@article{arxiv.2110.06658,
title = {Large-Gap Quantum Spin Hall State and Temperature-Induced Lifshitz Transition in Bi4Br4},
author = {Ming Yang and Yundan Liu and Wei Zhou and Chen Liu and Dan Mu and Yani Liu and Jiaou Wang and Weichang Hao and Jin Li and Jianxin Zhong and Yi Du and Jincheng Zhuang},
journal= {arXiv preprint arXiv:2110.06658},
year = {2021}
}