Decoupling Transition I. Flux Lattices in Pure Layered Superconductors

TL;DR

This paper investigates the decoupling transition of flux lattices in layered superconductors, revealing the nature of the transition, critical temperatures, and plasma frequency behavior using renormalization group analysis.

Contribution

It demonstrates that the decoupling transition is always continuous and provides quantitative estimates of critical temperatures and plasma frequency using RG methods.

Findings

Transition is continuous according to RG analysis.

Critical temperature scales as 1/B for weak J and 1/√B for strong J.

Renormalization group effectively evaluates Josephson plasma frequency.

Abstract

We study the decoupling transition of flux lattices in a layered superconductors at which the Josephson coupling J is renormalized to zero. We identify the order parameter and related correlations; the latter are shown to decay as a power law in the decoupled phase. Within 2nd order renormalization group we find that the transition is always continuous, in contrast with results of the self consistent harmonic approximation. The critical temperature for weak J is ~1/B, where B is the magnetic field, while for strong J it is~1/sqrt{B} and is strongly enhanced. We show that renormaliztion group can be used to evaluate the Josephson plasma frequency and find that for weak J it is~1/BT^2 in the decoupled phase.