Physical Review B
Mott transition in the one-dimensional SU (n) Hubbard model
E. Szirmai, Jenő Sólyom
Abstract
The one-dimensional SU$(n)$ Hubbard model is investigated using an analytical, perturbative renormalization-group treatment in the fermionic formulation of the model for $n>2$. It is found that in the half-filled case, the umklapp processes couple the spin and charge degrees of freedom and generate a finite gap for arbitrary finite positive $U$. This behavior is thus different from that at $1∕n$ filling, where there is one particle per site, in which case the dynamics of the two degrees of freedom can be separated and a critical ${U}_{\mathrm{c}}$ is needed for the Mott transition.