title: Correlation-Enhanced Odd-Parity Interorbital Singlet Pairing in the Iron-Pnictide Superconductor LiFeAs.
abstract: The rich variety of iron-based superconductors and their complex electronic structure lead to a wide range of possibilities for gap symmetry and pairing components. Here we solve in the two-Fe Brillouin zone the full frequency-dependent linearized Eliashberg equations to investigate spin-fluctuations mediated Cooper pairing for LiFeAs. The magnetic excitations are calculated with the random phase approximation on a correlated electronic structure obtained with density functional theory and dynamical mean field theory. The interaction between electrons through Hund's coupling promotes both the intraorbital d_{xz(yz)} and the interorbital magnetic susceptibility. As a consequence, the leading pairing channel, conventional s^{+-}, acquires sizable interorbital d_{xy}-d_{xz(yz)} singlet pairing with odd parity under glide-plane symmetry. The combination of intra- and interorbital components makes the results consistent with available experiments on the angular dependence of the gaps observed on the different Fermi surfaces.
authors.affiliation: Département de Physique and Institut quantique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Nourafkan
authors.affiliation: Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019, USA.
authors.forename: G
authors.initials: G
authors.lastname: Kotliar
authors.affiliation: Département de Physique and Institut quantique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada.|Quantum Materials Program, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada.
authors.forename: A-M S
authors.initials: AS
authors.lastname: Tremblay