Critical disorder effects in Josephson-coupled quasi-one-dimensional superconductors

TL;DR

This paper investigates how non-magnetic disorder affects the critical temperature and diamagnetism in quasi-one-dimensional superconductors, revealing disorder-induced phase transitions and divergence in penetration depth components.

Contribution

It introduces a model considering random Josephson coupling energies, showing how disorder destroys phase coherence and induces quantum critical behavior at zero temperature.

Findings

Disorder causes a discontinuous vanishing of T_c at a critical value.

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

Quantum phase transition of first-order at T=0 due to disorder.

Abstract

Effects of non-magnetic randomness on the critical temperature T_c and diamagnetism are studied in a class of quasi-one dimensional superconductors. 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 the wires and T_c vanishes discontinuously when the randomness reaches a critical value. The parallel and transverse components of the penetration depth are found to diverge at different critical temperatures T_c^{(1)} and T_c, which correspond to pair-breaking and phase-coherence breaking. The interplay between disorder and quantum phase fluctuations results in quantum critical behavior at T=0, manifesting itself as a superconducting-normal metal phase transition of first-order at a critical disorder strength.