Dzyaloshinskii-Moriya作用对Blume-Capel模型热力学性质的影响

Thermodynamic Effects of the Dzyaloshinskii—Moriya Interaction on the Blume—Capel Model

应用二自旋集团平均场近似的方法,研究了蜂窝格子上具有Dzyaloshinskii-Moriya(DM)作用的Blume-Capel模型的临界性质,得到了该系统的相图。结果表明,此系统存在三临界点,并且三临界点不是随DM作用参量单调变化。系统的这种临界行为可以解释为交换耦合作用、晶体场作用和DM作用三者之间相互竞争的结果。

Using the two--spin cluster mean--field method, the effects of the Dzyaloshinskii-- Moriya interaction on the thermodynamic properties of the Blume--Capel model are investigated for the honeycomb lattice. The phase diagram of this system is obtained, and it is found that the system exhibits the tricritical point. The tricritical point does not mo- notonously change with the DM interaction increasing. The critical properties of the system may be interpreted as a result of a competition among the exchange interaction , the crystal field interaction and the DM interaction.