single crystals*

Extensive study of over a dozen f-electron based Topological Kondo Insulator (TKI) candidate materials, such as SmB₆ and Ce₃Bi₄Pt₃, have led to a deep understanding of the role localized f-electrons play in the formation of a robust bulk correlated energy gap along with topologically protected surface conduction states in these materials. Recently, however, the observation of surface states and Kondo-like behavior in some d-electron materials is beginning to motivate further research to expand the understanding of TKIs into a new class of potential TKIs which include FeSi and FeSb₂. Using the inverted resistance method of separating bulk and surface contributions to electronic transport, our recent results have unambiguously demonstrated direct evidence of metallic surface conduction in FeSb₂ at low temperatures, revealing 2D metallic behavior on the surface of an extraordinarily robust insulating bulk single crystal. We have expanded this effort to probe the magnetic field dependence and symmetry of the surface conduction states in FeSb₂ while investigating the contributions to the transport behavior from intrinsic crystalline anisotropy as well as extrinsic surface and bulk defects.