Structure and phase stability of alloys based on systematic first principles thermodynamics calculations

统计热力学在现代材料科学中起着至关重要的作用。化合物的自由能是讨论相稳定性所不可缺少的。一般来说，自由能与温度有关的现象有很多种。在多组分体系中，原子组态对自由能有重要贡献。用密度泛函理论计算和团簇展开方法对构型效应进行了估算。因此，提出了基于密度泛函理论和CE方法的构型性质计算方法。我们构造了一个准二元系的基态结构和相图。此外，通过第一性原理分子动力学计算，估算了有限温度下的平均结构。

Statistical thermodynamics plays a crucial role in modern materials science. The free energy of compounds is indispensable for discussing the phase stability. In general, a number of phenomena contribute to the temperature dependence of the free energy. In multicomponent systems, an important contribution to the free energy arises from the atomic configuration. The configurational effects have been estimated by density functional theory calculations and the cluster expansion method. Therefore, methodologies for computing the configurational properties, based on DFT calculations and the CE method, are proposed. We have constructed ground state structures and phase diagrams for a pseudobinary MgO-ZnO and MgO-NiO systems. In addition, the average structure at a finite temperature has been estimated by carrying out first-principles molecular dynamics calculations.