title: Incommmensurability and unconventional superconductor to insulator transition in the hubbard model with bond-charge interaction.
abstract: 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>0 at half-filling. For large enough X<t the model shows three phases. For large U the system is in the spin-density wave phase as 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.
authors.affiliation: Comisión Nacional de Energía Atómica, Centro Atómico Bariloche and Instituto Balseiro, 8400 S.C. de Bariloche, Argentina.
authors.forename: A A
authors.initials: AA
authors.lastname: Aligia
authors.forename: A
authors.initials: A
authors.lastname: Anfossi
authors.forename: L
authors.initials: L
authors.lastname: Arrachea
authors.forename: C
authors.initials: C
authors.lastname: Degli Esposti Boschi
authors.forename: A O
authors.initials: AO
authors.lastname: Dobry
authors.forename: C
authors.initials: C
authors.lastname: Gazza
authors.forename: A
authors.initials: A
authors.lastname: Montorsi
authors.forename: F
authors.initials: F
authors.lastname: Ortolani
authors.forename: M E
authors.initials: ME
authors.lastname: Torio