Vacancy induced expansion of spin-liquid regime in J1-J2 Heisenberg model

Fuente: arXiv
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Main Authors: Dash, Soumyaranjan, Koley, Anish, Kumar, Sanjeev
Format: Preprint
Published: 2025
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author Dash, Soumyaranjan
Koley, Anish
Kumar, Sanjeev
author_facet Dash, Soumyaranjan
Koley, Anish
Kumar, Sanjeev
contents We study the model for spin-1/2 J1-J2 Heisenberg antiferromagnets on a square lattice in the presence of spin vacancies. In order to overcome the methodological challenges associated with analyzing models with magnetic frustration and inhomogeneities, we introduce a new semi-classical approach in which singlet dimers are treated as effective classical degrees of freedom. The energetic and entropic aspects of the dimer formation are included via a classical Monte Carlo scheme that allows for the dynamical conversion of spin pairs into dimers and vice versa. We show that our semi-classical approach recovers the qualitative physics of the J1-J2 model in the absence of vacancies. The vacancies lead to a broadening of the spin-liquid regime between the Néel and the stripe antiferromagnetic phases. This suggests a possible new route to discover spin-liquid ground states by tuning the J2/J1 ratio in doped square lattice antiferromagnets.
format Preprint
id arxiv_https___arxiv_org_abs_2507_20561
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Vacancy induced expansion of spin-liquid regime in J1-J2 Heisenberg model
Dash, Soumyaranjan
Koley, Anish
Kumar, Sanjeev
Strongly Correlated Electrons
We study the model for spin-1/2 J1-J2 Heisenberg antiferromagnets on a square lattice in the presence of spin vacancies. In order to overcome the methodological challenges associated with analyzing models with magnetic frustration and inhomogeneities, we introduce a new semi-classical approach in which singlet dimers are treated as effective classical degrees of freedom. The energetic and entropic aspects of the dimer formation are included via a classical Monte Carlo scheme that allows for the dynamical conversion of spin pairs into dimers and vice versa. We show that our semi-classical approach recovers the qualitative physics of the J1-J2 model in the absence of vacancies. The vacancies lead to a broadening of the spin-liquid regime between the Néel and the stripe antiferromagnetic phases. This suggests a possible new route to discover spin-liquid ground states by tuning the J2/J1 ratio in doped square lattice antiferromagnets.
title Vacancy induced expansion of spin-liquid regime in J1-J2 Heisenberg model
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2507.20561