Fermi surface and pairing symmetries in the two-dimensional Hubbard model

Quantum Monte Carlo is used to calculate various pairing correlations of the 2D Hubbard model possessing band features experimentally observed in the cuprates. In the hole-doped case, where the Fermi level lies close to the van Hove singularities around $(0,π)$ , the d $_{x^2-y^2}$ pairing correlation is selectively enhanced, while in the electron-doped case, where the singularities are far below the Fermi level and the Fermi surface runs through $(\pm π/2,\pm π/2)$ , both d $_{x^2-y^2}$ and d $_{xy}$ correlations are enhanced with the latter having a $\sqrt{2}\times \sqrt{2}$ structure. The two pairing symmetries can mix to result in a nodeless gap.Quantum Monte Carlo is used to calculate various pairing correlations of the 2D Hubbard model possessing band features experimentally observed in the cuprates. In the hole-doped case, where the Fermi level lies close to the van Hove singularities around $(0,π)$, the d$_{x^2-y^2}$ pairing correlation is selectively enhanced, while in the electron-doped case, where the singularities are far below the Fermi level and the Fermi surface runs through $(\pm π/2,\pm π/2)$, both d$_{x^2-y^2}$ and d$_{xy}$ correlations are enhanced with the latter having a $\sqrt{2}\times \sqrt{2}$ structure. The two pairing symmetries can mix to result in a nodeless gap.

arXiv:cond-mat/9710019Journal of the Physical Society of JapanMay 15, 199821 citations

Fermi surface of the 2D Hubbard model at weak coupling

Christoph J. Halboth, Walter Metzner

arXiv:cond-mat/9610216Zeitschrift für Physik B Condensed MatterDec 1, 199721 citations

(0,π)

, the d

_{x^2-y^2}

pairing correlation is selectively enhanced, while in the electron-doped case, where the singularities are far below the Fermi level and the Fermi surface runs through

(\pm π/2,\pm π/2)

, both d

_{x^2-y^2}

and d

_{xy}

correlations are enhanced with the latter having a

\sqrt{2}\times \sqrt{2}

structure. The two pairing symmetries can mix to result in a nodeless gap.