Disorder-driven superconductor-normal metal phase transition in quasi-one-dimensional organic conductors

TL;DR

This paper investigates how non-magnetic disorder affects superconductivity in quasi-one-dimensional organic conductors, revealing a first-order phase transition driven by disorder that destroys phase coherence and superconductivity.

Contribution

It introduces a model considering random Josephson coupling energies, demonstrating how disorder leads to a discontinuous vanishing of T_c and quantum critical behavior at zero temperature.

Findings

T_c vanishes discontinuously at a critical disorder strength.

Different critical temperatures for pair-breaking and phase coherence breaking.

Quantum critical behavior manifests as a first-order transition at T=0.

Abstract

Effects of non-magnetic disorder on the critical temperature T_c and on diamagnetism of quasi-one-dimensional superconductors are reported. The energy of Josephson-coupling between wires is considered to be random, which is typical for dirty organic superconductors. We show that this randomness destroys phase coherence between wires and that T_c vanishes discontinuously at a critical disorder-strength. The parallel and transverse components of the penetration-depth are evaluated. They diverge at different critical temperatures T_c^{(1)} and T_c, which correspond to pair-breaking and phase-coherence breaking respectively. The interplay between disorder and quantum phase fluctuations is shown to result in quantum critical behavior at T=0, which manifests itself as a superconducting-normal metal phase transition of first-order at a critical disorder strength.