\(\sqrt{3}\times\sqrt{3}\) Structure on the Triangular Lattice
1985; Physical Society of Japan; Volume: 54; Issue: 8 Linguagem: Inglês
10.1143/jpsj.54.2955
ISSN1347-4073
Autores Tópico(s)Opinion Dynamics and Social Influence
ResumoAn Ising model with nearest neighbor antiferromagnetic and next nearest neighbor ferromagnetic interactions is studied by the phenomenological renormalization method. The phase transition to the \(\sqrt{3}\times\sqrt{3}\) structure is of the second order for weak fields, and the critical exponents \(y_{\text{T}}{\cong}1.2\) and \(\eta{\cong}0.30\) are consistent with the conjectured values of the 3-state Potts model. Beyond a tricritical point the transition becomes of the first order for strong fields. The tricritical exponent \(y_{\text{T,t}}{\cong}1.73\) and \(\eta_{\text{t}}{\cong}0.21\) are also in agreement with the 3-state Potts tricritical values y T,t 3P =12/7 and η t 3P =4/21. The XY-like phase transition at zero fields, which was obtained by the Monte Carlo simulations, is not found in the present calculation.
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