Mesoscopic gap fluctuations in an unconventional superconductor

Abstract

We study mesoscopic disorder fluctuations in an anisotropic gap superconductor, which lead to the spatial variations of the local pairing temperature and formation of superconducting islands above the mean-field transition. We derive the probability distribution function of the pairing temperatures and superconducting gaps. It is shown that above the mean-field transition, a disordered BCS superconductor with an unusual pairing symmetry is described by a network of superconducting islands and metallic regions with a strongly suppressed density of states due to superconducting fluctuations. We argue that the phenomena associated with mesoscopic disorder fluctuations may also be relevant to the high-temperature superconductors, in particular, to recent STM experiments, where gap inhomogeneities have been explicitly observed. It is suggested that the gap fluctuations in the pseudogap phase should be directly related to the corresponding fluctuations of the pairing temperature.

4 pages, 2 figures; (v2: Two references added; v3: As published - A figure added, typos corrected)

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Cited by in corpus (10)

• Phase diagram of iron-pnictides if doping acts as a disorder
• Stable topological phases in a family of two-dimensional fermion models
• Infinite randomness fixed point of the superconductor-metal quantum phase transition
• Dynamical conductivity at the dirty superconductor-metal quantum phase transition
• Theory of the pairbreaking superconductor-metal transition in nanowires
• Non-perturbative microscopic theory of superconducting fluctuations near a quantum critical point
• Effect of weak disorder on the phase competition in iron pnictides
• Non-perturbative Quantum Dynamics of the Order Parameter in the Pairing Model
• Extended strange metal regime from superconducting puddles
• Short-range antiferromagnetic correlations in the superconducting state of filled skutterudite alloys Pr${}_{1-x}$Eu${}_x$Pt${}_4$Ge${}_{12}$