Coexistence of superconductivity and antiferromagnetism in a self-doped bilayert−t′−Jmodel

Abstract

A self-doped bilayer $t\text{\ensuremath{-}}{t}^{\ensuremath{'}}\text{\ensuremath{-}}J$ model of an electron- and a hole-doped planes is studied by the slave-boson mean-field theory. In our model, a renormalized interlayer hopping connects the differently doped planes, which is generated by a site potential. We find coexistent phases of antiferromagnetic (AFM) and superconducting orders, although the magnitudes of order parameters become more dissimilar in the bilayer away from half-filling. Fermi surfaces (FS's) with the AFM order show two pockets around the nodal and the antinodal regions. These results can be interpreted as a coexistence of electron- and hole-doped Fermi pockets in the bilayer. In the nodal direction, the FS splitting is absent even in the bilayer system, since one band has a gap due to the AFM order.