Topological surface states on Bi$_{1-x}$Sb$_x$: Dependence on surface orientation, surface termination and stability

摘要

Topological insulators support metallic surface states whose existence isprotected by the bulk band structure. It has been predicted early that thetopology of the surface state Fermi contour should depend on several factors,such as the surface orientation and termination and this raises the question towhat degree a given surface state is protected by the bulk electronic structureupon structural changes. Using tight-binding calculations, we explore thisquestion for the prototypical topological insulator Bi$_{1-x}$Sb$_x$, studyingdifferent terminations of the (111) and (110) surfaces. We also consider theimplications of the topological protection for the (110) surfaces for thesemimetals Bi and Sb