High-temperature superconductivity in dimer array systems

Superconductivity in the Hubbard model is studied on a series of lattices in which dimers are coupled in various types of arrays. Using fluctuation exchange method and solving the linearized Eliashberg equation, the transition temperature T-c of these systems is estimated to be much higher than that of the Hubbard model on a simple square lattice, which is a model for the high-T-c cuprates. We conclude that these 'dimer array' systems can generally exhibit superconductivity with very high T-c. Not only d-electron systems, but also p-electron systems may provide various stages for realizing the present mechanism.