Influence of Gap Extrema on the Tunneling Conductance Near an Impurity in an Anisotropic Superconductor

TL;DR

This paper investigates how impurities affect tunneling conductance in anisotropic superconductors, revealing that conductance variations depend on gap extrema location and symmetry, with implications for STM experiments.

Contribution

It provides a detailed analysis of impurity effects on tunneling conductance considering different gap symmetries and Fermi surface features in anisotropic superconductors.

Findings

Conductance variation depends on the Fermi surface location of gap extrema.

Different gap symmetries produce distinct spatial conductance features.

Impurity effects are detectable with STM on high-temperature superconductor surfaces.

Abstract

Changes: figures added in postscript form, Eq. (7) and various typos corrected. 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 an STM measurement on the surface of a high-temperature superconductor.