Quantum Monte Carlo study of the disordered attractive Hubbard model

Article

关键词: SUPERCONDUCTOR-INSULATOR TRANSITION;    COHERENCE LENGTH SUPERCONDUCTORS;    UNIVERSAL CONDUCTIVITY;    2-DIMENSIONAL FILMS;    FERMION SYSTEMS;    BOSE SYSTEMS;    NORMAL-STATE;    BOSONS;    LOCALIZATION;    DENSITY;   

DOI  :  10.1103/PhysRevB.59.4364

来源: SCIE

【 摘 要 】

We investigate the disorder-driven superconductor to insulator quantum phase transition (SIT) in an interacting fermion model using determinantal quantum Monte Carlo (QMC) methods. The disordered superconductor is modeled by an attractive Hubbard model with site disorder chosen randomly from a uniform distribution. The superconducting state which exists for small disorder is shown to evolve into an insulating phase beyond a critical disorder. The transition is tracked by the vanishing of (a) the superfluid stiffness, and (b) the charge stiffness or the delta function peak in the optical conductivity at zero frequency. We also show the behavior of the charge, spin, pair, and current correlations in the presence of disorder. Results for the temperature dependence of the de conductivity, obtained by an approximate analytic continuation technique, an also presented both in the metallic phase above T-c and the insulating phase. We discuss some of the complications in extracting the resistance at the transition point. [S0163-1829(99)00306-9].

【 授权许可】

Free