title: s± pairing near a Lifshitz transition.
abstract: Observations of robust superconductivity in some of the iron based superconductors in the vicinity of a Lifshitz point where a spin density wave instability is suppressed as the hole band drops below the Fermi energy raise questions for spin-fluctuation theories. Here we discuss spin-fluctuation pairing for a bilayer Hubbard model, which goes through such a Lifshitz transition. We find s± pairing with a transition temperature that peaks beyond the Lifshitz point and a gap function that has essentially the same magnitude but opposite sign on the incipient hole band as it does on the electron band that has a Fermi surface.
authors: Joint Institute of Computational Sciences, University of Tennessee, Knoxville, TN-37996, USA.
authors: Vivek
authors: V
authors: Mishra
authors: Department of Physics, University of California, Santa Barbara, CA-93106, USA.
authors: Douglas J
authors: DJ
authors: Scalapino
authors: Computer Science and Mathematics Division &Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN-37831, USA.
authors: Thomas A
authors: TA
authors: Maier