Extended Impurity Potential in a d_{x^2-y^2} Superconductor

TL;DR

This paper explores how a finite-range impurity potential affects the local density of states in a d_{x^2-y^2} superconductor, revealing enhanced features that aid in experimental observation of anisotropic modulations.

Contribution

It introduces the concept of extended impurity potentials and analyzes their impact on local density of states in d-wave superconductors, extending previous models.

Findings

Impurity-induced subgap resonances are altered by additional scattering channels.

The local density of states shows enhanced structure near impurities.

Results facilitate better observation of anisotropic spatial modulations.

Abstract

We investigate the role of a finite potential range of a nonmagnetic impurity for the local density of states in a d_{x^2-y^2} superconductor. Impurity induced subgap resonances are modified by the appearance of further scattering channels beyond the $s$--wave scattering limit. The structure of the local density of states (DOS) in the vicinity of the impurity is significantly enhanced and therefore improves the possibility for observing the characteristic anisotropic spatial modulation of the local DOS in a d_{x^2-y^2} superconductor by scanning tunneling microscopy.