Superconductivity and Pseudogaps in the Hubbard Model and Copper Oxide Superconductors

Y. F. Kung, Cheng-Chien Chen, Elizabeth Nowadnick +3 more

J. González, F. Guinea, M.A.H. Vozmediano

Emanuel Gull, Olivier Parcollet, Andrew J. Millis

Recently developed numerical methods have enabled the explicit construction of the superconducting state of the Hubbard model of strongly correlated electrons in parameter regimes where the model also exhibits a pseudogap and a Mott insulating phase. d(x(2)-y(2)) symmetry superconductivity is found to occur in proximity to the Mott insulator, but separated from it by a pseudogapped nonsuperconducting phase. The superconducting transition temperature and order parameter amplitude are found to be maximal at the onset of the normal-state pseudogap. The emergence of superconductivity from the normal state pseudogap leads to a decrease in the excitation gap. All of these features are consistent with the observed behavior of the copper-oxide superconductors.

Rene Jursa, S. Wermbter, G. Czycholl

L.F. Sampaio, E.J. Calegari, José Jesús Rodríguez-Núñez +2 more

Emanuel Gull, Andrew J. Millis

Cluster dynamical mean field methods are used to calculate the superconductivity-induced changes in the interplane conductivity and Raman scattering cross section of the two-dimensional Hubbard model. When superconductivity emerges from the pseudogap, the superconducting response is found to be diminished in amplitude, broadened, and, in the case of the interplane conductivity, shifted to higher frequency. The results are in agreement with data on high-temperature copper-oxide superconductors indicating that the Hubbard model contains the essential low-energy physics of the pseudogap and its interplay with superconductivity in the cuprates.