Cooper Pairing in Insulating Valence Band in Fe-Based Superconductors
Abstract
Conventional Cooper pairing arises from attractive interaction of electrons in the metallic bands. Recent experiment on Co-doped LiFeAs shows superconductivity in the insulating valence band, which is evolved from a metallic hole band upon doping. Here we examine this phenomenon by studying superconductivity in a three-orbital Hamiltonian relevant to the doped LiFeAs. We show explicitly that Cooper pairing of the insulating hole band requires a finite pairing interaction strength. For strong coupling, the superconductivity in the hole band is robust against the sink of the hole band below the Fermi level. Our theory predicts a substantial upward shift of the chemical potential in the superconducting transition for Co-doped LiFeAs.
Cite
@article{arxiv.1502.04285,
title = {Cooper Pairing in Insulating Valence Band in Fe-Based Superconductors},
author = {Lun-Hui Hu and Wei-Qiang Chen and Fu-Chun Zhang},
journal= {arXiv preprint arXiv:1502.04285},
year = {2015}
}
Comments
5 pages, 5 figures