Ground-state phase diagram of the one-dimensional $t$-$J_s$-$J_{\tau}$ model at quarter filling

TL;DR

This paper investigates the ground-state phase diagram of a one-dimensional $t$-$J_s$-$J_{ au}$ model with an additional channel degree of freedom, revealing various phases and the effects of channel fluctuations.

Contribution

It introduces and analyzes the phase diagram of a generalized $t$-$J$ model with a channel degree of freedom using DMRG, identifying new phases and transition mechanisms.

Findings

Identification of multiple phases including Tomonaga-Luttinger liquid, spin-gap, and insulator.

Weak channel fluctuations stabilize the spin-gap state.

Strong channel fluctuations induce a transition to the insulator.

Abstract

We study the ground state of the one-dimensional "$t$-$J_s$-$J_{\tau}$ model," which is a variant of the $t$-$J$ model with additional channel degree of freedom. The model is not only a generalization of the $t$-$J$ model but also an effective model of the two-channel Kondo lattice model in the strong-coupling region. The low-energy excitations and correlation functions are systematically calculated by the density matrix renormalization group method, and the ground-state phase diagram at quarter filling consisting of a Tomonaga-Luttinger liquid, spin-gap state, channel-gap state, insulator, and phase separation is determined. We find that weak channel fluctuations stabilize the spin-gap state, while strong channel fluctuations lead to the transition to the insulator.