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Microscopic description of d-wave superconductivity by Van Hove nesting in the Hubbard model

J. Gonzalez
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Abstract

We devise a computational approach to the Hubbard model that captures the strong coupling dynamics arising when the Fermi level is at a Van Hove singularity in the density of states. We rely on an approximate degeneracy among the many-body states accounting for the main instabilities of the system (antiferromagnetism, d-wave superconductivity). The Fermi line turns out to be deformed in a manner consistent with the pinning of the Fermi level to the Van Hove singularity. For a doping rate $δ\sim 0.2$, the ground state is characterized by d-wave symmetry, quasiparticles gapped only at the saddle-points of the band, and a large peak at zero momentum in the d-wave pairing correlations.

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J. Gonzalez. 2000-04-27. Microscopic description of d-wave superconductivity by Van Hove nesting in the Hubbard model. https://doi.org/10.1103/physrevb.63.024502

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