Two s-wave solutions for superconductivity in the extended Hubbard model

M. Bak

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arXiv · cond-mat/0406143

Two s-wave solutions for superconductivity in the extended Hubbard model

M. Bak

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Abstract

The existence of more than one solution for s-wave pairing in the extended Hubbard model is not often realized. This possibility was noted by Friedberg et al. [Phys. Rev B50, 10190 (1994)] in the case of two electrons on a lattice, without further analysis. In the present paper, the second solution is found also in the case of superconductivity of extended s-wave symmetry in the extended Hubbard model. The properties of both s-wave solutions are examined by mean-field methods and thresholds for their appearance are given. A possibility of the first-order transition is discovered and modifications of the phase diagram are calculated. Results of this paper in the limit of low electron density are also applicable to the bound, two-electron pairs.

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M. Bak. 2004-07-01. Two s-wave solutions for superconductivity in the extended Hubbard model. https://arxiv.org/abs/cond-mat/0406143

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