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

TitleAnisotropy of the pairing gap of FeAs-based superconductors induced by spin fluctuations
Publication TypeJournal Article
Year of Publication2009
AuthorsSknepnek R, Samolyuk G, Lee YB, Schmalian J
Journal TitlePhysical Review B
Volume79
Pages054511
Date Published02/01
ISBN Number1098-0121
Accession NumberISI:000263815400085
Keywordsfermi surface, fluctuations in superconductors, iron compounds, magnetic anisotropy, order, systems, type ii superconductors
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 J(H). We find that for sufficiently large J(H), 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.

URL<Go to ISI>://000263815400085
DOI10.1103/Physrevb.79.054511