Phase diagram of the two-dimensional negative-<i>U</i> Hubbard model

R. T. Scalettar; E. Y. Loh; J. E. Gubernatis; A. Moreo; S. R. White; D. J. Scalapino; R. L. Sugar; E. Dagotto

doi:10.1103/PhysRevLett.62.1407

Phase diagram of the two-dimensional negative-U Hubbard model

R. T. Scalettar, E. Y. Loh, J. E. Gubernatis, A. Moreo, S. R. White, D. J. Scalapino, R. L. Sugar, and E. Dagotto

Phys. Rev. Lett. 62, 1407 – Published 20 March 1989; Erratum Phys. Rev. Lett. 63, 218 (1989)

Abstract

Theoretical arguments and numerical calculations are used to discuss the phase diagram of the two-dimensional negative-U Hubbard model. Our results are consistent with (1) a vanishing transition temperature at half-filling but with a ground state having both superconducting and charge-density-wave long-range order, and (2) a Kosterlitz-Thouless transition at a finite temperature into a superconducting state with power-law decay of the pairing correlations away from half-filling.