Destruction of Superconductivity by Impurities in the Attractive Hubbard Model

Abstract

We study the effect of U=0 impurities on the superconducting and thermodynamic properties of the attractive Hubbard model on a square lattice. Removal of the interaction on a critical fraction of $f_{\mathrm{crit}}\approx 0.30$ of the sites results in the destruction of off-diagonal long range order in the ground state. This critical fraction is roughly independent of filling in the range $0.75<\rho <1.00$, although our data suggest that $f_{\mathrm{crit}}$ might be somewhat larger below half-filling than at $\rho =1$. We also find that the two peak structure in the specific heat is present at $f$ both below and above the value which destroys long range pairing order. It is expected that the high $T$ peak associated with local pair formation should be robust, but apparently local pairing fluctuations are sufficient to generate a low temperature peak.

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• s-wave Superconductivity Phase Diagram in the Inhomogeneous Two-Dimensional Attractive Hubbard Model
• Localization and Superconductivity in Doped Semiconductors
• Local suppression of the superfluid density of PuCoGa${}_5$ in the Swiss Cheese model
• Disordered two-dimensional superconductors: roles of temperature and interaction strength
• Dynamical resilience to disorder: the dilute Hubbard model on the Lieb lattice
• Interplay of Superconductivity and Spin-Dependent Disorder
• Percolation on Lieb lattices
• Phase Diagram of the Attractive Hubbard Model with Inhomogeneous Interactions
• Effect of site dilution in the two-dimensional attractive Hubbard model
• Pair correlations and the survival of superconductivity in and around a super-conducting impurity