A topological material in the III-V family: heteroepitaxial InBi on InAs

TL;DR

This study demonstrates the existence of topological electronic surface states in heteroepitaxial InBi grown on InAs, revealing novel surface terminations and their influence on topological properties through experimental and theoretical analysis.

Contribution

It presents the first observation of topological surface states in heteroepitaxial InBi within the III-V family, highlighting the role of Bi bilayer termination in topological behavior.

Findings

Topological surface states observed near the M bar high symmetry point.

Bi bilayer termination is crucial for the topological surface electronic structure.

Theoretical models support the experimental findings and clarify surface state origins.

Abstract

InBi(001) is formed epitaxially on InAs(111)-A by depositing Bi on to an In-rich surface. Angle-resolved photoemission measurements reveal topological electronic surface states, close to the M bar high symmetry point. This demonstrates a heteroepitaxial system entirely in the III-V family with topological electronic properties. InBi shows coexistence of Bi and In surface terminations, in contradiction with other III-V materials. For the Bi termination, the study gives a consistent physical picture of the topological surface electronic structure of InBi(001) terminated by a Bi bilayer rather than a surface formed by splitting to a Bi monolayer termination. Theoretical calculations based on relativistic density functional theory and the one-step model of photoemission clarify the relationship between the InBi(001) surface termination and the topological surface states, supporting a predominant role of the Bi bilayer termination. Furthermore, a tight-binding model based on this Bi bilayer termination with only Bi-Bi hopping terms, and no Bi-In interaction, gives a deeper insight into the spin texture.