Phase diagram of dirty two-band superconductors and observability of impurity-induced s + i s state
Silaev, M., Garaud, J., & Babaev, E. (2017). Phase diagram of dirty two-band superconductors and observability of impurity-induced s + i s state. Physical Review B, 95 (2), 024517. doi:10.1103/PhysRevB.95.024517
Julkaistu sarjassaPhysical Review B
© 2017 American Physical Society. Published in this repository with the kind permission of the publisher.
We investigate the phase diagram of dirty two-band superconductors. This paper primarily focuses on the properties and observability of the time-reversal symmetry-breaking s + is superconducting states, which can be generated in two-band superconductors by interband impurity scattering. We show that such states can appear in two distinct ways. First, according to a previously discussed scenario, the s + is state can form as an intermediate phase at the impurity-driven crossover between s± and s++ states. We show that there is a second scenario where domains of the s + is state exists in the form of an isolated dome inside the s± domain, completely detached from the transition between s± and s++ states. We demonstrate that in both cases the s + is state generated by impurity scattering exists in an extremely small interval of impurity concentrations. Although this likely precludes direct experimental observation of the s + is state formation due to this mechanism, this physics leads to the appearance of a region inside both the s± and s++ domains with unusual properties due to softening of normal modes. ...