STM/STS studies of the surface of Bi2Se3

Building upon previous work,\footnote{Urazhdin S. et al. Physical Review B 69, 085313 (2004); Physical Review B 66, 161306(R) (2002).} we apply scanning tunneling microscopy/spectroscopy to characterize the surface of the topological insulator Bi2Se3. We see clover-like defect states in the topographic scans and a residual image that appears in conductance scans, which we attribute to Bi substitutions in Se lattice sites. Spectroscopy reveals features in the density of states consistent with the topological surface state, with the defect states appearing as an additional enhancement. We will discuss the interaction of the topological surface state with the defect states.