Spinon-holon interactions in an anisotropic t-J chain: a comprehensive study

TL;DR

This study investigates how anisotropic interactions in a one-dimensional t-J model influence spinon-holon binding, revealing a transition from bound states to free excitations as anisotropy varies, supported by analytic and numerical analysis.

Contribution

It provides a comprehensive analysis of spinon-holon interactions in an anisotropic t-J chain, including explicit predictions for binding energy dependence on anisotropy.

Findings

Binding energy interpolates between finite and zero as anisotropy varies.

Anisotropy induces effective attraction leading to bound states.

Spinon dispersion changes drive the non-trivial behavior.

Abstract

We consider a generalization of the one-dimensional t-J model with anisotropic spin-spin interactions. We show that the anisotropy leads to an effective attractive interaction between the spinon and holon excitations, resulting in a localized bound state. Detailed quantitative analytic predictions for the dependence of the binding energy on the anisotropy are presented, and verified by precise numerical simulations. The binding energy is found to interpolate smoothly between a finite value in the t-Jz limit and zero in the isotropic limit, going to zero exponentially in the vicinity of the latter. We identify changes in spinon dispersion as the primary factor for this non-trivial behavior.