Year: 2014
Type: article
Abstract: We study the role of impurities in a two-band superconductor, and elucidate the nature of the recently predicted transition from the ${s}_{\ifmmode\pm\else\textpm\fi{}}$ state to the ${s}_{++}$ state induced by interband impurity scattering. Using a Ginzburg-Landau theory, derived from microscopic equations, we demonstrate that close to ${T}_{c}$ this transition is necessarily a direct one, but deeper in the superconducting state an intermediate complex state appears. This state has a distinct order parameter, which breaks the time-reversal symmetry, and is separated from the ${s}_{\ifmmode\pm\else\textpm\fi{}}$ and ${s}_{++}$ states by continuous phase transitions. Based on our results, we suggest a phase diagram for systems with weak repulsive interband pairing, and discuss its relevance to iron-based superconductors.
Source: Physical Review B
Authors: Valentin Stanev, Alexei E. Koshelev
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: U.S. Department of Education
Awards: G3363948808, G3591473356
OpenAlex ID: W2090640833