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

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 (1) c 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.