Ground-State Phase Diagram of the XXZ Model on a Railroad-Trestle Lattice with Asymmetric Leg Interactions

TL;DR

This study explores how asymmetry in leg interactions affects the ground-state phase diagram of the XXZ model on a railroad-trestle lattice, revealing that certain phase transition lines are sensitive to asymmetry while others are not.

Contribution

The paper demonstrates that asymmetry influences the dimer/spin-fluid transition line but not the dimer/Neel transition line in the XXZ model on a railroad-trestle lattice.

Findings

Asymmetry does not significantly alter the dimer/Neel transition line.

Asymmetry affects the dimer/spin-fluid transition line.

Only the doublet excitation is impacted by asymmetric interactions.

Abstract

Using the bosonization and level spectroscopy methods, we study the ground-state phase diagram of a XXZ antiferromagnet on a railroad-trestle lattice with asymmetric leg interactions. It is shown that the asymmetry does not change the dimer/Neel transition line significantly, which agrees with the expectation based on a naive bosonization procedure, but it does change the dimer/spin-fluid transition line. To understand this observation, we analyze eigenvectors of the ground state, dimer excitation, doublet excitation and Neel excitation, and find that only the doublet excitation is affected by the asymmetric interaction.