Coexistence of antiferromagnetism and superconductivity of t-t′-J model on honeycomb lattice

Motivated by recent experimental study of antiferromagnetic property of honeycomb compound In3Cu2VO9 [Yan et al. (2012)], we explore possible superconductivity and its coexistence with collinear antiferromagnetism. Explicitly, we use the t-t′-J model on the honeycomb lattice as our starting point and employ the slave-boson mean-field theory. In the antiferromagnetic normal state, the characteristic doping evolution of Fermi surface shows that only one effective singe band is active, which suggests that the potential pairing symmetry is more likely the time-reversal symmetry breaking d+id, rather than the extended s-wave pairing structure. It is found that this superconducting state coexists with the antiferromagnetism in a broad doping regime, which is consistent with the numerical calculations. The local density of states and its thermodynamic property of the superconducting state has been studied in detail with an effective single-band picture for understanding other physical observable such as superfluid density. The present work may be useful in experimentally exploring possible superconductivity of this kind of materials on the honeycomb lattice and contributes to the understanding of the unconventional superconductivity on general two-dimensional correlated electron systems.