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arXiv · 1712.07914

Raising the critical temperature by disorder in unconventional superconductors mediated by spin fluctuations

Astrid T. Roemer·P. J. Hirschfeld·Brian M. Andersen
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Abstract

We propose a mechanism whereby disorder can enhance the transition temperature Tc of an unconventional superconductor with pairing driven by exchange of spin fluctuations. The theory is based on a self-consistent real space treatment of pairing in the disordered one-band Hubbard model. It has been demonstrated before that impurities can enhance pairing by softening the spin fluctuations locally; here, we consider the competing effect of pair-breaking by the screened Coulomb potential also present. We show that, depending on the impurity potential strength and proximity to magnetic order, this mechanism results in a weakening of the disorder-dependent Tc-suppression rate expected from Abrikosov-Gor'kov theory, or even in disorder-generated Tc enhancements.

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Astrid T. Roemer, P. J. Hirschfeld, Brian M. Andersen. 2018-08-02. Raising the critical temperature by disorder in unconventional superconductors mediated by spin fluctuations. https://doi.org/10.1103/physrevlett.121.027002

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