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Destruction of Superconductivity by Impurities in the Attractive Hubbard Model

Daniel Hurt·Evan Odabashian·Warren Pickett·Richard Scalettar·Felipe Mondaini·Thereza Paiva·Raimundo R. dos Santos
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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 $f_{\rm crit} \approx 0.30$ 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 $0.75 < ρ< 1.00$, although our data suggest that $f_{\rm crit}$ might be somewhat larger below half-filling than at $ρ=1$. 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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Daniel Hurt, Evan Odabashian, Warren Pickett, Richard Scalettar, Felipe Mondaini, Thereza Paiva, Raimundo R. dos Santos. 2005-07-08. Destruction of Superconductivity by Impurities in the Attractive Hubbard Model. https://doi.org/10.1103/physrevb.72.144513

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