On the effect of localized and delocalized quasiparticles on a nonlinear conductivity of superconductors

TL;DR

This paper critically examines the claim that surface-bound quasiparticles influence the nonlinear surface resistance of superconductors, arguing that previous models are incorrect and do not support the existence of such bound states affecting conductivity.

Contribution

The paper refutes prior claims about surface-bound quasiparticles affecting superconducting surface resistance and demonstrates inaccuracies in existing phenomenological models.

Findings

Surface-bound quasiparticles do not significantly affect $R_s$.

Existing models incorrectly predict the field and temperature dependence of $R_s$.

The supposed impact of bound states on nonlinear conductivity is not supported by the analysis.

Abstract

Recently Deyo et al. [\prb {\bf 106}, 104502 (2022)] suggested that the surface resistance $R_s(H_0)$ of a superconductor under strong electromagnetic field can be affected by field-induced quasiparticle bound states at the surface. This Comment shows that the existence of such bound states and their contribution to $R_s$ are not substantiated and the phenomenological models of Ref. \cite{corn} give incorrect field and temperature dependencies of $R_s(T,H_0)$.