Superconductivity in a Correlated E ⊗ e Jahn-Teller System

By numerically solving the Eliashberg equation in the RPA as well as employing the Landau's theory for phase transitions, we have investigated superconductivity, especially its pairing character, in a two-orbital Hubbard model coupled with EaSue Jahn-Teller phonons on a two-dimensional square lattice at half filling. If the electron hopping between neighboring sites keeps the orbital character invariant in this EaSue Jahn-Teller crystal, we find that a new superconducting phase characterized by the pairing of spin singlet, orbital singlet, and odd in momentum space, named a chiral p-wave pairing, is brought about by the collaboration of orbital fluctuations enhanced mainly by the electron-phonon interaction with spin fluctuations induced by the electron-electron one.