Vortex viscosity in the moderately clean limit of layered superconductors

TL;DR

This paper provides a microscopic analysis of energy dissipation in vortex cores of layered superconductors in the moderately clean regime, confirming the applicability of the quasiclassical Bardeen--Stephen result across different vortex motion speeds.

Contribution

It demonstrates that the quasiclassical dissipation formula remains valid in the moderately clean limit, even with strong energy level correlations, for both fast and slow vortex dynamics.

Findings

Quasiclassical expression applies in fast vortex motion with level transitions.

Quasiclassical expression applies in slow, adiabatic vortex motion.

Results relate to similar findings in random-matrix models.

Abstract

We present a microscopic calculation of the energy dissipation in the core of a vortex moving in a two-dimensional or layered superconductor in the moderately clean regime. In this regime, the quasiclassical Bardeen--Stephen result remains valid in spite of the strong correlations between the energy levels. We find that the quasiclassical expression applies both in the limit of fast vortex motion (with transitions between smeared levels) and in the limit of slow vortex motion (with nearly adiabatic dynamics). This finding can be related to the similar result known for the unitary random-matrix model.