Spin-gap phase in the extended t-J chain

TL;DR

This paper analyzes the one-dimensional extended t-J model using continuum field theories, identifying two phases—Luttinger and Luther-Emery liquids—and highlighting the dominance of singlet superconducting correlations in the latter.

Contribution

It provides a theoretical phase diagram of the extended t-J chain, distinguishing phases based on t'/t ratios and their correlation properties.

Findings

Identification of Luttinger and Luther-Emery phases

Dominance of singlet superconducting correlations in Luther-Emery phase

Phase boundary at a critical t'/t ratio

Abstract

We study the one-dimensional deformed $t-t^{\prime}-J$ model in terms of the continuum field theories. We found that at low doping concentration and far away from the phase separation regime, there are two phases: the Luttinger liquid and the Luther-Emery liquid, depending on t'/t<(t'/t)_c or t'/t>(t'/t)_c, where (t'/t)_c>0. Moreover, the singlet superconducting correlations are dominant in the Luther-Emery liquid.