Anisotropy of the pairing gap of FeAs-based superconductors induced by spin fluctuations

Rastko Sknepnek, German Samolyuk, Yong-bin Lee, Joerg Schmalian

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    Abstract

    We determine the anisotropy of the spin-fluctuation-induced pairing gap on the Fermi surface of the FeAs-based superconductors as function of the exchange and Hund's coupling JH. We find that for sufficiently large JH, nearly commensurate magnetic fluctuations yield a fully gapped s±-pairing state with small anisotropy of the gap amplitude on each Fermi-surface sheet, but significant variations of the gap amplitude for different sheets of the Fermi surface. In particular, we obtain the large variation of the gap amplitude on different Fermi-surface sheets, as seen in angular resolved photoemission spectroscopy experiments. For smaller values of Hund's coupling incommensurate magnetic fluctuations yield an s±-pairing state with line nodes. Such a state is also possible once the anisotropy of the material is reduced and three-dimensional effects come into play.

    Original languageEnglish
    Article numberARTN 054511
    Number of pages9
    JournalPhysical Review B: Condensed Matter and Materials Physics
    Volume79
    Issue number5
    DOIs
    Publication statusPublished - Feb 2009

    Keywords

    • Systems
    • Type II superconductors
    • Magnetic anisotropy
    • Fluctuations in superconductors
    • Order
    • Iron compounds
    • Fermi surface

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