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 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.
Incommensurability and unconventional superconductor to insulator transition in the Hubbard model with bond-charge interaction / A. A. Aligia; A. Anfossi; L. Arrachea; C. Degli Esposti Boschi; A. O. Dobry; C. Gaaza; A. Montorsi; F. Ortolani; M. E. Torio. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - STAMPA. - 99:(2007), pp. 206401-1-206401-4.
Incommensurability and unconventional superconductor to insulator transition in the Hubbard model with bond-charge interaction.
DEGLI ESPOSTI BOSCHI, CRISTIAN;ORTOLANI, FABIO;
2007
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 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.