Disorder effect in low dimensional superconductors

TL;DR

This paper investigates how non-magnetic impurities affect the electronic properties of two-dimensional s- and d-wave superconductors, revealing that scattering potential range influences impurity effects more than pairing symmetry.

Contribution

It demonstrates that the scattering potential range is more critical than pairing symmetry in impurity effects, and compares localization lengths in different superconducting states.

Findings

Impurity effects depend more on scattering potential range than pairing symmetry.

Localization length is longer in d-wave superconductors than in the normal state.

Impurities influence specific heat and transition temperature in Zn-doped YBCO.

Abstract

The quasiparticle density of states (DOS), the energy gap, the superfluid density $\rho_s$, and the localization effect in the s- and d-wave superconductors with non-magnetic impurity in two dimensions (2D) are studied numerically. For strong (unitary) scatters, we find that it is the range of the scattering potential rather than the symmetry of the superconducting pairing which is more important in explaining the impurity dependences of the specific heat and the superconducting transition temperature in Zn doped YBCO. The localization length is longer in the d-wave superconducting state than in the normal state, even in the vicinity of the Fermi energy.