各向异性晶场中横向Ising模型的相图

Phase Diagrams of the Transverse Ising Model with Anisotropic Crystal-Field

用相关有效场理论研究在各向异性晶场中自旋s=3 /2横向Ising模型的磁性质 ,给出该Ising模型的相变公式 ,具体计算了具有配位数为 3的蜂窝点阵的系统相变温度·结果表明各向异性晶场和横向磁场对具有蜂窝点阵的系统的相变温度有很大影响 ,当横向磁场小于 0 4 57时 ,无论各向异性晶场取值多大 ,转变温度都不会降到零 ,而当横向磁场降为零时 ,转变温度将趋近于常数 0 52 5,另外所有在相变点发生的相变皆为二级相变·

The spin 3/2 transverse Ising model with anisotropic crystal field on honeycomb lattice (z=3) has been studied by using the effective field theory with correlations. The general expressions for evaluating the second order phase transition temperatures are obtained. The results show that both the transverse field and crystal field have important effects on the phase diagram of the Ising system. The transition temperatures do not always fall to zero when Ω/|J|<0 457. They approach a constant value 0 525 for large negative D(D→-∞) without transverse field (Ω=0). On the other hand, it is shown that all phase transformations are second order.