Unconventional superconductivity in iron-base superconductors in a three-band model

Abstract

Iron-base superconductors exhibits features of systems where the Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) phase, a superconducting state with non-zero total momentum of Cooper pairs, is actively sought. Experimental and theoretical evidence points strongly to the FFLO phase in these materials above the Pauli limit. In this article we discuss the ground state of iron-base superconductors near the critical magnetic field and the full $h-T$ phase diagram for pnictides in case of intra-band pairing, in a three-band model with $s_{\pm}$ symmetry.