面心立方格子上自旋S=1的Ising反铁磁体的基态研究

本文发展了文献1]中提出的利用费密变换求Ising模型基态的方法,根据由费密变换后,激发态能量大于零求得相边界,提出了直接比较各真空态能量来求解各基态的相边界。采用此方法,研究了具有近邻对相互作用的最一般的自旋S=1的Ising反铁磁体模型,严格地求得它在面心立方格子上的基态能量和零温相图。同时,还利用多相点方程,将参数k,l平面分成60个小区域,它们分别对应于各个拓扑不等价的零温相图。 关键词：

GROUND STATE STUDY OF SPIN S = 1 ISING ANTIFER-ROMAGNETIC MODEL ON FACE-CENTRED CUBIC LATTICE

This paper develops the method presented in reference (1) where the Fermion transformation is used to obtain the ground state of the Ising model. According to that after the Ferrnion transformation, the phase boundary can be obtain using the condition that energy of excited state is greater than zero, we propose that phase boundary can be obtain by directly comparing the energy of the vacuum state. Using this method, we study the most general spin S=1 Ising antifer-romagnetic model with nearest neighbor interaction, and obtain rigorously the ground state energy and the OK phase diagram of the model on fcc lattice. Meanwhile, using equation of many phase point, we divide the plane of parameter k,l into 56 regions, which correspond to topologi-cally distinct OK phase diagrams.