Topological Defect-Phase Soliton and the Pairing Symmetry of a Two-Band Superconductor: Role of the Proximity Effect

Abstract

We suggest a mechanism which promotes the existence of a phase soliton—a topological defect formed in the relative phase of superconducting gaps of a two-band superconductor with s+− type of pairing. This mechanism exploits the proximity effect with a conventional s-wave superconductor which favors the alignment of the phases of the two-band superconductor which, in the case of s+− pairing, are π shifted in the absence of proximity. In the case of a strong proximity such an effect can be used to reduce the soliton’s energy below the energy of a soliton-free state, thus making the soliton thermodynamically stable. Based on this observation we consider an experimental setup, applicable for both stable and metastable solitons, which can be used to distinguish between s+− and s++ types of pairing in the iron-based multiband superconductors.

Source-reported materials — not catalogue approval

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