Scanning tunneling microscopy of superconducting topological surface states in Bi\(_2\)Se\(_3\)

In this paper we present scanning tunneling microscopy of a large \(\textrm{Bi}_2\textrm{Se}_3\) crystal with superconducting PbBi islands deposited on the surface. Local density of states measurements are consistent with induced superconductivity in the topological surface state with a coherence length of order 540 nm. At energies above the gap the density of states exhibits oscillations due to scattering caused by a nonuniform order parameter. Strikingly, the spectra taken on islands also display similar oscillations along with traces of the Dirac cone, suggesting an inverse topological proximity effect.