Local Electronic Structure Around a Single Impurity in Superconductors

Abstract

In this chapter, I am going to discuss the local electronic structure around a single impurity. Both the nonmagnetic and magnetic impurity scattering in conventional s-wave and unconventional d-wave superconductors will be considered. The local electron density of states and the existence of impurity bound or virtual bound states will be explored. The possible realization of Majorana zero-energy modes is discussed for the case of electrons coupled to a spin chain in an s-wave superconductor. These results have a direct relevance to the STM measurements. The results will also be compared with the T-matrix method.