title: High T_{c} via Spin Fluctuations from Incipient Bands: Application to Monolayers and Intercalates of FeSe.
abstract: We investigate superconductivity in a two-band system with an electronlike and a holelike band, where one of the bands is away from the Fermi level (or "incipient"). We argue that the incipient band contributes significantly to spin-fluctuation pairing in the strong coupling limit where the system is close to a magnetic instability and can lead to a large T_{c}. In this case, T_{c} is limited by a competition between the frequency range of the coupling (set by an isolated paramagnon) and the coupling strength itself, such that a domelike T_{c} dependence on the incipient band position is obtained. The coupling of electrons to phonons is found to further enhance T_{c}. The results are discussed in the context of experiments on monolayers and intercalates of FeSe.
authors: Department of Physics, University of Florida, Gainesville, Florida 32611, USA.
authors: A
authors: A
authors: Linscheid
authors: Department of Physics, University of Florida, Gainesville, Florida 32611, USA.
authors: S
authors: S
authors: Maiti
authors: Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA.
authors: Y
authors: Y
authors: Wang
authors: Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA.
authors: S
authors: S
authors: Johnston
authors: Department of Physics, University of Florida, Gainesville, Florida 32611, USA.
authors: P J
authors: PJ
authors: Hirschfeld