Interpocket pairing and gap symmetry in Fe-based superconductors with only electron pockets

M. Khodas*, A. V. Chubukov

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

112 Scopus citations

Abstract

We analyze the pairing symmetry in Fe-based superconductors AFe 2Se 2 (A=K, Rb, Cs) which contain only electron pockets. We argue that the pairing condensate in such systems contains not only intrapocket component but also interpocket component, made of fermions belonging to different electron pockets. We analyze the interplay between intrapocket and interpocket pairing, depending on the ellipticity of electron pockets and the strength of their hybridization. We show that with increasing hybridization, the system undergoes a transition from a d-wave state to an s + - state, in which the gap changes sign between hybridized pockets. This s +- state has the full gap and at the same time supports spin resonance, in agreement with the data. Near the boundary between d and s +- states, we found a long-sought s+id state which breaks time-reversal symmetry.

Original languageAmerican English
Article number247003
JournalPhysical Review Letters
Volume108
Issue number24
DOIs
StatePublished - 15 Jun 2012
Externally publishedYes

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