  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.
