paper

Spatially nonuniform phases in the one-dimensional SU(n) Hubbard model for commensurate fillings

arXiv:0708.3799 · doi:10.1103/PhysRevB.77.045106

Abstract

The one-dimensional repulsive SU Hubbard model is investigated analytically by bosonization approach and numerically using the density-matrix renormalization-group (DMRG) method for , and 5 for commensurate fillings where and are relatively prime. It is shown that the behavior of the system is drastically different depending on whether , , or . When , the umklapp processes are irrelevant, the model is equivalent to an -component Luttinger liquid with central charge . When , the charge and spin modes are decoupled, the umklapp processes open a charge gap for finite , whereas the spin modes remain gapless and the central charge . The translational symmetry is not broken in the ground state for any . On the other hand, when , the charge and spin modes are coupled, the umklapp processes open gaps in all excitation branches, and a spatially nonuniform ground state develops. Bond-ordered dimerized, trimerized or tetramerized phases are found depending on the filling.

10 pages, 11 figures

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