Possible high-Tc superconductivity mediated by antiferromagnetic spin fluctuations in systems with Fermi surface pockets -: art. no. 024501

We propose that if there are two small pocketlike Fermi surfaces, and the spin susceptibility is pronounced around a wave vector Q that bridges the two pockets, the spin-singlet superconductivity mediated by spin fluctuations may have a high transition temperature. Using the fluctuation exchange approximation, this idea is confirmed for the Hubbard on a lattice with alternating hopping integrals, for which T-c is estimated to be almost an order of magnitude larger than those for systems with a large connected Fermi surface.