Electronic properties of the trellis-lattice Hubbard model: Pseudogap and superconductivity

We study the electronic states of the two-dimensional frustrated coupled ladder (trellis lattice) Hubbard model, which is a theoretical model of the superconducting material Sr14-xCaxCu24O41.Temperature dependence of the density of states and magnetic susceptibility are discussed by using the fluctuation exchange method, which is applied to this model for the first time. At half filling, a large pseudogap appears in the density of states at higher temperatures. Moreover, the d-wave superconductivity appears at lower temperatures, where the pseudogap is well developed. These behaviors have similarities to the under-doped high-T-c, cuprates.