Dual thermal pseudocritical features in a spin-1/2 Ising chain with twin-diamond geometry

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Détails bibliographiques
Auteur principal:	Rojas, Onofre
Format:	Preprint
Publié:	2025
Sujets:	Statistical Mechanics
Accès en ligne:	Acceder al recurso
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_version_	1866910027589091328
author	Rojas, Onofre
author_facet	Rojas, Onofre
contents	We study the coupled twin-diamond chain, a decorated one-dimensional Ising model motivated by the magnetic structure of $\mathrm{Cu}_{2}(\mathrm{TeO}_{3})_{2}\mathrm{Br}_{2}$. By applying an exact mapping to an effective Ising chain, we obtain the full thermodynamic description of the system through a compact transfer-matrix formulation. The ground-state analysis reveals five distinct phases, including two frustrated sectors with extensive degeneracy. These frustrated regions give rise to characteristic entropy plateaus and separate the ordered phases in the zero-temperature diagram. At low temperatures the model exhibits peculiar sharp yet continuous variations of entropy, magnetization, and response functions, reflecting clear signatures of pseudotransition behavior. The coupled twin-diamond chain thus provides an exactly solvable setting in which competing local configurations and internal frustration lead to pronounced dual pseudocritical features in one dimension.
format	Preprint
id	arxiv_https___arxiv_org_abs_2511_18596
institution	arXiv
publishDate	2025
record_format	arxiv
spellingShingle	Dual thermal pseudocritical features in a spin-1/2 Ising chain with twin-diamond geometry Rojas, Onofre Statistical Mechanics We study the coupled twin-diamond chain, a decorated one-dimensional Ising model motivated by the magnetic structure of $\mathrm{Cu}_{2}(\mathrm{TeO}_{3})_{2}\mathrm{Br}_{2}$. By applying an exact mapping to an effective Ising chain, we obtain the full thermodynamic description of the system through a compact transfer-matrix formulation. The ground-state analysis reveals five distinct phases, including two frustrated sectors with extensive degeneracy. These frustrated regions give rise to characteristic entropy plateaus and separate the ordered phases in the zero-temperature diagram. At low temperatures the model exhibits peculiar sharp yet continuous variations of entropy, magnetization, and response functions, reflecting clear signatures of pseudotransition behavior. The coupled twin-diamond chain thus provides an exactly solvable setting in which competing local configurations and internal frustration lead to pronounced dual pseudocritical features in one dimension.
title	Dual thermal pseudocritical features in a spin-1/2 Ising chain with twin-diamond geometry
topic	Statistical Mechanics
url	https://arxiv.org/abs/2511.18596

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