自旋S=3/2和S=2 Blume-Capel模型相变的Monte Carlo研究  

MONTE CARLO STUDY OF THE PHASE DIAGRAMS OF S = 3/2 AND S=2 BLUME-CAPLE MODEL

作　　者：张国民[1] 杨传章[1] 

机构地区：[1]苏州大学物理系,苏州215006

出　　处：《物理学报》1995年第6期958-962,共5页Acta Physica Sinica

摘　　要：利用计算机Monte Carlo模拟,研究自旋S=3/2和S=2 Blume-Capel模型的相图。与最近刚发展起来的适用于研究S>1的关联有效场相比较,得出如下结论:对于S=3/2和S=2,关联有效场过高地估计了它们的相变温度;对于S=3/2的相图,除了有二级相变线外,还发现了一级相变线;对于S=2,关联有效场同样过高地估计了三临界点的值。We studied the phase diagrams of S= 3/2 and S=2 Blume-Caple model by using Monte Carlo computer simulations. A comparison with the new effective field theory with correlations makes us to draw the following conclusion: Effective field theory with correlations overestimates the critical temperatures for both S= 3/2 and S=2 Blume-Caple model. For S= 3/2, besides a second order transition occur-ring at high temperature, there exists a first order transition line occurring in the low temperature region. For S= 2. the effective field theory also overestimates the tricritical point in the phase diagram.

关 键 词：相变 B-C模型 相图 伊辛模型 

分 类 号：O482.5[理学—固体物理]