Impurities and Quasi-One Dimensional Transport in a D-wave Superconductor

TL;DR

This paper investigates impurity effects in d-wave superconductors, revealing a quasi-one-dimensional scattering regime at low temperatures and predicting impurity-dependent conductivity influenced by weak localization effects.

Contribution

It introduces a new quasi-one-dimensional scattering regime in d-wave superconductors with finite impurity potential range, relevant at low temperatures.

Findings

Quasi-one-dimensional scattering occurs in high-Tc superconductors below 10 K.

Impurity scattering leads to weak localization of quasiparticles in the orthogonal class.

Dc conductivity is proportional to the normal state scattering rate and depends on impurity concentration.

Abstract

Impurity scattering in the unitary limit produces low energy quasiparticles with anisotropic spectrum in a two-dimensional $d$-wave superconductor. We describe a new {\em quasi-one-dimensional } limit of the quasiparticle scattering, which might occur in a superconductor with short coherence length and with {\em finite} impurity potential range. The dc conductivity in a $d$-wave superconductor is predicted to be proportional to the normal state scattering rate and is impurity-{\em dependent}. We show that the {\em quasi-one-dimensional } regime occurs in high-$T_c$ superconductors at low temperatures $T\lesssim 10$~K. We argue that the impurities produce weak localization, in the {\em orthogonal } universality class, of the quasiparticles in a $d$-wave superconductor.