Incommmensurability and unconventional superconductor to insulator transition in the Hubbard model with bond-charge interaction

Aligia, A. A.; Anfossi, A.; Arrachea, L.; Boschi, C. Degli Esposti; Dobry, A. O.; Gazza, C.; Montorsi, A.; Ortolani, F.; Torio, M. E.

Incommmensurability and unconventional superconductor to insulator transition in the Hubbard model with bond-charge interaction

Authors

Aligia, A. A.

Anfossi, A.

Arrachea, L.

Boschi, C. Degli Esposti

Description

We determine the quantum phase diagram of the one-dimensional Hubbard model with bond-charge interaction X in addition to the usual Coulomb repulsion U at half-filling. For large enough X and positive U the model shows three phases. For large U the system is in the spin-density wave phase already known in the usual Hubbard model. As U decreases, there is first a spin transition to a spontaneously dimerized bond-ordered wave phase and then a charge transition to a novel phase in which the dominant correlations at large distances correspond to an incommensurate singlet superconductor.
5 pages, 3 figures