Determine the origin and topological character of FeSb2 surface states

Determine whether the metallic surface states observed on FeSb2 are topologically nontrivial, reconstruction-induced, disorder-related, or manifestations of a more general correlated surface electronic structure.

Background

FeSb2 is a correlated narrow-gap semiconductor and a candidate 3d-electron Kondo insulator that exhibits metallic surface states and a low-temperature resistance plateau associated with possible surface-dominated conduction. However, several mechanisms could account for the observed surface states, including nontrivial band topology, surface reconstruction, disorder, or correlation-driven in-gap electronic structure.

Clarifying the microscopic origin of these states is important for determining whether the resistance plateau and surface metallicity reflect topological boundary states or a more general correlated surface phenomenon. The paper explicitly identifies this issue as unresolved, while noting that existing band-structure calculations do not fully capture the observed surface states.