Moiré pattern modulated topological phase and in-gap edge modes in α-antimonene

Abstract

Using a simple sequential deposition method, we grow black-phosphorus-like antimonene (α-antimonene) on top of α-bismuthene nanoislands. Due to the lattice mismatch between the α-antimonene overlayer and the bismuthene bases, the heterostructure exhibits a moiré pattern whose periodicitiy (∼8 ± 1 nm) is amongst the largest periodicities ever observed in 2D systems. We use scanning tunnelling microscopy and spectroscopy to show that this moiré pattern modulates both the electronic states in the bulk and the edge states of the α-antimonene, and therefore leads to local modulations of the topological phase. We present calculations which elucidate the effects of strain on the bandstructure of α-Sb and discuss detailed spectroscopy results for the edge states, as well as the effect of interlayer interactions between the α-Sb and α-Bi structures.