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The Attractive Hubbard Model in 2-D: Is It Capable of Describing a Pseudogap and Preformed Pairs?

Martin Letz

arXiv:cond-mat/9807383Journal of SuperconductivityFeb 1, 19993 citations

Tc and pseudogap in the 2-D attractive Hubbard model

José Jesús Rodríguez-Núñez, Sandra Schafroth, H. Beck +3 more

Physica B Condensed MatterFeb 1, 19952 citations

Pseudogap in the one-electron spectral functions of the attractive Hubbard model

Massimiliano Capezzali, Hans Beck

arXiv:cond-mat/9806211Physica B Condensed MatterJan 1, 19998 citations

ATTRACTIVE HUBBARD MODEL AND SINGLE-PARTICLE PSEUDOGAP CAUSED BY CLASSICAL PAIRING FLUCTUATIONS IN TWO-DIMENSIONS

Yu. M. Vil’k, S. Allen, Hugo Touchette +3 more

arXiv:cond-mat/9710013Journal of Physics and Chemistry of SolidsOct 1, 199819 citations

Pair-fluctuation-induced pseudogap in the normal phase of the two-dimensional attractive Hubbard model at weak coupling

Daniel Rohe, Walter Metzner

One-particle spectral properties in the normal phase of the two-dimensional attractive Hubbard model are investigated in the weak-coupling regime using the non-self-consistent T-matrix approximation. The corresponding equations are evaluated numerically directly on the real-frequency axis. For temperatures sufficiently close to the superconducting transition temperature, a pseudogap in the one-particle spectral function is observed, which can be assigned to the increasing importance of pair fluctuations.One-particle spectral properties in the normal phase of the two-dimensional attractive Hubbard model are investigated in the weak-coupling regime using the non-self-consistent T-matrix approximation. The corresponding equations are evaluated numerically directly on the real-frequency axis. For temperatures sufficiently close to the superconducting transition temperature, a pseudogap in the one-particle spectral function is observed, which can be assigned to the increasing importance of pair fluctuations.

arXiv:cond-mat/0011500Physical review. B, Condensed matterMay 22, 200147 citations

PSEUDOGAP, CHARGE AND SPIN RESPONSES IN THE HUBBARD MODEL

Y. M. Malozovsky, J. D. Fan

We have studied in terms of the effective T-matrix the self-energy part for both the attractive (U<0) and repulsive (U>0) Hubbard models. It is shown that the fluctuation pairing for strong coupling at T>T c for the attractive Hubbard model does not cause any pseudogap behavior in the single-particle density of states. We have also identified the origin of the false pseudogap for that case. Meanwhile, the fluctuation pairing significantly affect the density–density and the current–current correlation functions. As a result, there exists a pseudogap in the charge (and current) response for the attractive Hubbard model. In contrast, the pseudogap in the spin response appears to exist for the repulsive Hubbard model only. It is also shown that the contribution from the Hartree–"Cooper" channel gives an anomalous Fermi liquid term, Im χ c ≈-ω/T, to the charge response of the nearly antiferromagnetic Fermi liquid.We have studied in terms of the effective T-matrix the self-energy part for both the attractive (U<0) and repulsive (U>0) Hubbard models. It is shown that the fluctuation pairing for strong coupling at T>T c for the attractive Hubbard model does not cause any pseudogap behavior in the single-particle density of states. We have also identified the origin of the false pseudogap for that case. Meanwhile, the fluctuation pairing significantly affect the density–density and the current–current correlation functions. As a result, there exists a pseudogap in the charge (and current) response for the attractive Hubbard model. In contrast, the pseudogap in the spin response appears to exist for the repulsive Hubbard model only. It is also shown that the contribution from the Hartree–"Cooper" channel gives an anomalous Fermi liquid term, Im χ c ≈-ω/T, to the charge response of the nearly antiferromagnetic Fermi liquid.

International Journal of Modern Physics BDec 20, 199913 citations

Pairing fluctuations induced pseudogap in the Attractive Hubbard Model

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