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arXiv:cond-mat/0507213 · Physical Review B

Destruction of superconductivity by impurities in the attractive Hubbard model

Daniel Hurt, Evan Odabashian, Warren E. Pickett, Richard T. Scalettar, Felipe Mondaini, Thereza Paiva, Raimundo R. dos Santos

Published Oct 17, 2005• 16 citations
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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 ${f}_{\mathrm{crit}}\ensuremath{\approx}0.30$ 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 $0.75<\ensuremath{\rho}<1.00$, although our data suggest that ${f}_{\mathrm{crit}}$ might be somewhat larger below half filling than at $\ensuremath{\rho}=1$. 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.

DOI
10.1103/physrevb.72.144513

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