Motivated by the bad metal behavior of the iron pnictides, we study a multi-orbital t-J1-J2 model and investigate possible singlet superconducting pairings. Magnetic frustration by itself leads to a large degeneracy in the pairing states. The kinetic energy breaks this into a quasidegeneracy among a reduced set of pairing states. For small electron and hole Fermi pockets, an A1g state dominates over the phase diagram but a B1g state has close-by energy. In addition to the nodeless A 1g sx2y2 channel, the nodal A1g sx2+y2 and B1g dx2-y2 channels are also competitive in the magnetically frustrated J1 ∼ J2 parameter regime. An A1g +iB1g state, which breaks timereversal symmetry, occurs at low temperatures in part of the phase diagram. Implications for the experiments in the iron pnictides are discussed.
ASJC Scopus subject areas
- Physics and Astronomy(all)