Antiferromagnetism and chiral-d wave superconductivity in a honeycomb lattice close to Mott state

The antiferromagnetism (AFM) and chiral-d wave superconductivity (SC) in a honeycomb lattice close to an antiferromagnetic (AF) Mott state at half band filling are studied with a t−J model and slave boson mean field theory. The order parameters and single particle dispersion relations at different band filling fractions are investigated. It is found that the AFM enhances the SC, and leads to nodal single particle dispersion relations at two band filling fractions. These unexpected nodal dispersion relations out of nodeless chiral-d wave superconducting order are discussed. A comparison between AF chiral-d wave states and AF extended-s wave states is also given to highlight the pertinent features in chiral-d wave superconducting states. This study may be related to the honeycomb lattice materials such as the In3Cu2VO9 compound. •Antiferromagnetism in honeycomb lattice enhances superconductivity.•Antiferromagnetism in honeycomb lattice causes nodal superconducting states.•Antiferromagnetism induces nodal excitation out of nodeless superconducting orders.