First-Order Pairing Transition and Single-Particle Spectral Function in the Attractive Hubbard Model
Abstract
A dynamical mean-field theory analysis of the attractive Hubbard model in the normal phase is carried out upon restricting to solutions where superconducting order is not allowed. A clear first-order pairing transition as a function of the coupling takes place at all the electron densities out of half filling between a Fermi liquid, stable for U<Uc, and an insulating bound pairs phase for U>Uc, and it is accompanied by phase separation. The spectral function in the metallic phase is constituted by a low-energy structure around the Fermi level, which disappears discontinuously at U = Uc, and two high-energy features (Hubbard bands), which persist in the insulating phase.
- Publication:
-
Physical Review Letters
- Pub Date:
- March 2002
- DOI:
- 10.1103/PhysRevLett.88.126403
- arXiv:
- arXiv:cond-mat/0109194
- Bibcode:
- 2002PhRvL..88l6403C
- Keywords:
-
- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Superconductivity
- E-Print:
- 5 pages, 3 figures, accepted for publication in Physical Review Letters