Comment on ``Impurity states and the absence of quasiparticle localization in disordered d-wave superconductors''

TL;DR

This paper critiques a previous study on impurity states in disordered d-wave superconductors, providing corrected estimates that challenge earlier conclusions about impurity-induced transport and localization.

Contribution

It offers a revised calculation of impurity hopping matrix elements, disputing the prior assumption that impurity states form a network enabling transport in such superconductors.

Findings

Previous estimates of impurity hopping were incorrect.

Impurity states do not form a network capable of supporting transport.

The physical implications of the earlier model are invalid.

Abstract

In a recent Letter Balatsky and Salkola made their conclusion about the absence of localization in disordered d-wave superconductors exploiting the idea that strongly overlapping impurity states formed a network capable to provide the transport. We present here the correct estimate of hopping matrix elements between two impurities which were the basic quantities for the subsequent consideration in the abovementioned Letter. We conclude, that the picture of the impurity-impurity potential acting only within the slowly broadening tails claimed by Balatsky and Salkola as well as all the physical consequences of this picture appear to be incorrect.