Effects of domain walls on hole motion in the two-dimensional t-J model at finite temperature

TL;DR

This study uses quantum Monte Carlo simulations to explore how antiferromagnetic domain walls influence hole movement in the two-dimensional t-J model at finite temperatures, revealing temperature-dependent behaviors and potential hole pairing.

Contribution

It introduces a novel implementation of the Hoshen-Koppelman algorithm to identify AF domains and analyzes their impact on hole dynamics in the t-J model.

Findings

Holes tend to move along AF domain walls at higher temperatures.

Hole pairing indications emerge at relatively high temperatures.

System transitions from domain wall movement to within-phase movement as temperature decreases.

Abstract

The t-J model on the square lattice, close to the t-J_z limit, is studied by quantum Monte Carlo techniques at finite temperature and in the underdoped regime. A variant of the Hoshen-Koppelman algorithm was implemented to identify the antiferromagnetic domains on each Trotter slice. The results show that the model presents at high enough temperature finite antiferromagnetic (AF) domains which collapse at lower temperatures into a single ordered AF state. While there are domains, holes would tend to preferentially move along the domain walls. In this case, there are indications of hole pairing starting at a relatively high temperature. At lower temperatures, when the whole system becomes essentially fully AF ordered, at least in finite clusters, holes would likely tend to move within phase separated regions. The crossover between both states moves down in temperature as doping increases and/or as the off-diagonal exchange increases. The possibility of hole motion along AF domain walls at zero temperature in the fully isotropic t-J is discussed.