具有Dzyaloshinskii-Moriya作用的Blume-Capel模型的临界性质

Critical properties of the Blume-Capel model with the Dzyaloshinskii-Moriya interaction

应用二自旋集团平均场近似的方法,研究了蜂窝晶格和正方晶格上具有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,所研究系统存在三临界点,并且三临界温度不随DM作用参量单调变化,三临界温度有最小值。系统的这种临界性质是交换耦合作用、晶体场作用和DM作用三者相互竞争的结果。

Using the two - spin cluster mean - field method, the Blume - Capel models with the Dzyaloshinskii - Moriya （DM） interaction were studied for the honeycomb and square lattices. The phase diagrams of this systems were obtained, and it is found that systems exhibit the tricritical point. The tricritical temperature does not monotonously change with the DM interaction increasing, has a minimum. 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.