title: Possible mixed coupling mechanism in FeTe(1-x)Se(x) within a multiband Eliashberg approach.
abstract: We show that the phenomenology of the iron chalcogenide superconductor FeTe(1-x)Se(x) can be explained within an effective three-band s±-wave Eliashberg model. In particular, various experimental data reported in literature-the critical temperature, the energy gaps, the upper critical field, the superfluid density-can be reproduced by this model in a moderate strong-coupling regime provided that both an intraband phononic term and an interband antiferromagnetic spin-fluctuations term are included in the coupling matrix. The intraband coupling is unusual in Fe-based compounds and is required to explain the somehow anomalous association between gap amplitudes and Fermi surfaces, already evidenced by ARPES.
authors.affiliation: Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy. National Research Nuclear University MEPhI, Moscow Engineering Physics Institute, Kashira Hwy 31, Moskva 115409, Russia.
authors.forename: G A
authors.initials: GA
authors.lastname: Ummarino
authors.forename: D
authors.initials: D
authors.lastname: Daghero