Cluster mean-field theory study of J1-J2 Heisenberg model on a square lattice.
J Phys Condens Matter
; 26(11): 115601, 2014 Mar 19.
Article
em En
| MEDLINE
| ID: mdl-24589877
ABSTRACT
We study the spin-1/2 J1-J2 Heisenberg model on a square lattice using the cluster mean-field theory. We find a rapid convergence of phase boundaries with increasing cluster size. By extrapolating the cluster size L to infinity, we obtain accurate phase boundaries J(c1)(2) ≈ 0.42 (between the Néel antiferromagnetic phase and non-magnetic phase), and J(c2)(2) ≈ 0.59 (between non-magnetic phase and the collinear antiferromagnetic phase). Our results support the second-order phase transition at J(c1)(2) and the first-order one at J(c2)(2). For the spin-anisotropic J1-J2 model, we present its finite temperature phase diagram and demonstrate that the non-magnetic state is unstable towards the first-order phase transition under intermediate spin anisotropy.
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Base de dados:
MEDLINE
Assunto principal:
Teoria Quântica
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Compostos Ferrosos
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Modelos Estatísticos
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Transição de Fase
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Campos Magnéticos
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article