Quantum materials interfaces: Graphene/bismuth (111) heterostructures

Abstract

Heterostructures involving graphene and bismuth, with their ability to absorb light over a very wide energy range, are of interest for engineering next-generation optoelectronics. Critical to the technological application of such heterostructures is an understanding of the underlying physics governing their properties. Here, using first-principles calculations, we study the interfacial interactions between graphene and bismuth thin films. Our study reveals nonintuitive phenomena associated with the moiré physics of these superlattices. We show a preservation of graphene-derived Dirac cones in spite of proximity to a substrate with large spin-orbit coupling, a greater influence of graphene on the electronic structure properties of bismuth, and the surprising presence of a magnetic solution, only slightly higher in energy (by several meV) than the nonmagnetic structure, possibly validating experiments. Such subtle and unanticipated phenomena associated with the moiré physics are expected to play key roles in the practical applications of heterogeneous assemblies of two-dimensional quantum systems.