Topological phase transition and tunable electronic properties of hydrogenated bismuthene: from single-layer to double-layer

Abstract

Planar bismuthene grown on SiC substrate provides a promising candidate to engineer van der Waals doublelayer (DL) made of two dimensional (2D) topological insulators. We perform systematical calculations in DL hydrogenated bismuthene (HBi) that can be used to simulate the experimentally grown planar bismuthene to explore realizable 2D topological insulator van der Waals DL. Two possible geometry configurations of AA and ABstacked DL HBi are investigated. Due to pseudo JahnTeller effect, ABstacked DL HBi has a strong interlayer coupling interaction and shows buckled lattice. Particularly, both AA and ABstacked DL HBi are topologically trivial rather than topologically nontrivial. The physical origin of the trivial topology is clarified by analyzing orbital composition. We discuss how the electronic properties are modified by interlayer coupling, external strain, and metal atom intercalation. It is also found that, for ABstacked DL HBi, metal atom intercalation gives rise to novel multiple Rashba splitting near the valence band top, which is expected to manipulate the same spin in different planar bismuthene layers. Our results present various and tunable electronic properties of van der Waals DL HBi and allow for probing into multiple Rashba effect in 2D inversionasymmetric topological insulators.

Searching for kagome multi-bands and edge states in a predicted organic topological insulator

“…In essence, this collective symmetry breaking reminds of Jahn-Teller 58 and pseudo Jahn-Teller distortions 59 that are very efficient mechanisms to lift system's degeneracies that compete with other electronic interactions. [60][61][62]…”