We report on the derivation of analytical equations for ab-initio calculations of the strain dependence of crystal-electric-field (CEF) parameters for arbitrary deformations. The calculation is based on the fundamental assumption that the charge distribution deforms in the same way as the crystal. Based on this deformed-charge model, simple formulas for the practical usage are given for various site symmetries of cubic lattices under uniform strain. These formulas can be used to predict the change of the magnetic crystal-field anisotropy under strain, which is important for the design of magnetic materials and devices. As an example for the power of the method, we present a calculation of the magnetic contribution to the thermal expansion in some rare-earth-based materials.

我们报告了用于从头计算任意变形的晶体电场 (CEF) 参数的应变依赖性的解析方程的推导。该计算基于电荷分布以与晶体相同的方式变形的基本假设。基于该变形电荷模型，给出了均匀应变下立方晶格的各种位点对称性的简单实用公式。这些公式可用于预测应变下磁晶场各向异性的变化，这对磁性材料和器件的设计具有重要意义。作为该方法功效的一个示例，我们提供了一些稀土基材料中磁性对热膨胀的贡献的计算。