Influence of gap extrema on the tunneling conductance near an impurity in an anisotropic superconductor

Abstract

We examine the effect of an impurity on the nearby tunneling conductance in an anisotropically gapped superconductor. The variation of the conductance has pronounced spatial dependence which depends strongly on the Fermi surface location of gap extrema. In particular, different gap symmetries produce profoundly different spatial features in the conductance. These effects may be detectable with a scanning-tunneling-microscope study of the surface of a high-temperature superconductor.