ABSTRACT

The temperature dependence of the order parameters η (α-phase) and ξ (INC – incommensurate phase) are calculated in the presence of the electric field for the α-INC-β transition in quartz by the Landau mean field theory. Landau phenomenological model with the linear ($\eta \xi$) and quadratic (${\eta }^2{\xi }^2$) coupling is introduced to investigate mainly the nature of the INC phase between α (ordered) and β (disordered) phases in quartz. The temperature dependence of the inverse susceptibilities (${\chi }_{\eta }^{-1}$ and ${\chi }_{\xi }^{-1}$) of the order parameter is also predicted at constant electric fields studied for the α-INC-β transition in quartz. Additionally, the E−T phase diagram for the transitions of the α-INC and INC-β in quartz is constructed from the Landau phenomenological model by using the literature data. Our predictions for the order parameters (η and ξ) and the inverse susceptibilities (${\chi }_{\eta }^{-1}$ and ${\chi }_{\xi }^{-1}$) can be compared with the experimental measurements for the α-INC-β transition in quartz.

摘要

阶参数η（α相）和ξ（INC - 不公称相）的温度依赖性是在存在电场的情况下通过朗道平均场理论计算出的石英中的α -INC- β转变。Landau 现象学模型具有线性 ($\eta \xi$) 和二次方 (${\eta }^2{\xi }^2$) 耦合主要研究石英中α（有序）和β（无序）相之间的INC相的性质。逆磁化率的温度依赖性 (${\chi }_{\eta }^{-1}$ 和 ${\chi }_{\xi }^{-1}$) 的有序参数也在为石英中的α -INC- β跃迁研究的恒定电场中预测。此外，石英中α -INC和INC- β相变的E - T相图是利用文献数据从Landau现象学模型构建的。我们对阶参数（η和ξ）和逆磁化率（${\chi }_{\eta }^{-1}$ 和 ${\chi }_{\xi }^{-1}$) 可以与石英中α -INC- β转变的实验测量值进行比较。