Surface and electronic structure of SmB through scanning tunneling microscopy

Abstract

SmB, a so-called Kondo insulator, is recently discussed as a candidate material for a strong topological insulator. We present detailed atomically resolved topographic information on the (0 0 1) surface from more than a dozen SmB samples. Atomically flat, in situ cleaved surfaces often exhibit B- and Sm-terminated surfaces as well as reconstructed and non-reconstructed areas coexisting on different length scales. The terminations are unambiguously identified. In addition, electronic inhomogeneities are observed which likely result from the polar nature of the (0 0 1) surface and may indicate an inhomogeneous Sm valence at the surface of SmB. In addition, atomically resolved topographies on a (1 1 0) surface are discussed.