Metal-insulator phase transition in an exactly solvable model of nondegenerate interacting fermion chains

摘要

A two parametric family of the models of two coupled nondegenerate fermion chains is proposed and solved by the means of the Bethe ansatz. We give a detailed analysis of the exact zero-temperature phase diagram at half filling for different parameters of the interactions. It is shown that insulator and "interchain ferromagnetic" phase states are separated by "intermediate metallic" state, these phase states coexist in a tricritical point. The critical fluctuations are described by a conformal field theory with the central charge c=1. In the tricritical point the fermion state is described as a Luttinger liquid state with one gapless mode that is characterized by abnormal large density-density correlations and correlations of the momentum distribution function.