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 Tc. In this case, Tc 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 Tc dependence on the incipient band position is obtained. The coupling of electrons to phonons is found to further enhance Tc. The results are discussed in the context of experiments on monolayers and intercalates of FeSe.
Original language | English |
---|---|
Article number | 077003 |
Journal | Physical Review Letters |
Volume | 117 |
Issue number | 7 |
DOIs | |
State | Published - Aug 12 2016 |
Externally published | Yes |
Funding
The authors are grateful for useful discussions with T. Maier, V. Mishra, and D.J. Scalapino. P.J.H. and A.L. were supported by DOE Grant No.DE-FG02-05ER46236. S.J. and Y.W. are partially funded by the University of Tennessee's Science Alliance Joint Directed Research and Development (JDRD) program, a collaboration with Oak Ridge National Laboratory.