Unconventional superconducting symmetry in a checkerboard antiferromagnet studied via renormalized mean-field theory

摘要

We use a renormalized mean-field theory to study the Gutzwiller projected Bardeen-Cooper-Schrieffer states of the extended Hubbard model in the large U limit or the t-t'-J-J' model on a two-dimensional checkerboard lattice. At small t'/t, the frustration due to the diagonal terms of t' and J' does not alter the d_(x~2-y~2)-wave pairing symmetry, and the negative (positive) t'/t enhances (suppresses) the pairing order parameter. At large t'/t, the ground state has an s-s wave symmetry. At the intermediate t'/t, the ground state is d+id or d+is wave with time reversal symmetry broken.