Abstract
We propose a mechanism whereby disorder can enhance the transition temperature 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 -suppression rate expected from Abrikosov-Gor’kov theory, or even in disorder-generated enhancements.
- Received 21 December 2017
DOI:https://doi.org/10.1103/PhysRevLett.121.027002
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