Evidence of indium impurity band in superconducting (Sn,In)Te thin films

${\mathrm{Sn}}_{1\ensuremath{-}x}{\mathrm{In}}_{x}\mathrm{Te}$ has been synthesized and studied recently as a candidate topological superconductor. Its superconducting critical temperature increases with indium concentration. However, the role of indium in altering the normal-state band structure and generating superconductivity is not well understood. Here, we explore this question in ${\mathrm{Sn}}_{1\ensuremath{-}x}{\mathrm{In}}_{x}\mathrm{Te} (0