A first-principles method to calculate fourth-order elastic constants of solid materials
A first-principles method to calculate fourth-order elastic constants of solid materials
复制标题
DOI：
10.1016/j.cpc.2023.108751
复制
发表时间：
2023-02
期刊：
影响因子：
--
通讯作者：
Abhiyan Pandit;A. Bongiorno
中科院分区：
文献类型：
--
作者：
Abhiyan Pandit;A. Bongiorno
本文提出了计算立方和六方对称晶体四阶以下弹性常数的第一原理方法。该方法依赖于第二Piola-Kirchhoff应力张量的数值微分和密度泛函理论方法来计算参考态的一系列变形组态的柯西应力张量。对于立方和六方对称的晶体，计算二、三、四阶独立弹性常数所需的应变组态数分别为24和37。在这里，我们介绍了我们的方法的概念方面，我们提供了它的实现和使用的技术细节，我们评估了它的准确性，并讨论了几个应用。特别是，该方法适用于五种具有立方对称性的晶体材料(钻石、硅、铝、银和金)和两种具有六方紧密堆积结构的金属(铍和镁)。我们的结果与现有的实验数据和以前的计算研究进行了比较。在非线性弹性理论的背景下，计算的线性和非线性弹性常数也被用来预测压力区间内的体积和体积模量值。将这些预测与密度泛函理论计算得到的结果进行比较，以评估我们方法的可靠性。
Afirst-principlesmethod is presented to calculate elastic constants up to the fourth order of crystals with the cubic and hexagonal symmetries. The method relies on the numerical differentiation of the second Piola-Kirchhoff stress tensor and a density functional theory approach to calculate the Cauchy stress tensor for a list of deformed configurations of a reference state. The number of strained configurations required to calculate the independent elastic constants of the second, third, and fourth order is 24 and 37 for crystals with the cubic and hexagonal symmetries, respectively. Here, we present conceptual aspects of our method, we provide technical details of its implementation and use, we assess its accuracy, and we discuss several applications. In particular, this method is applied to five crystalline materials with the cubic symmetry (diamond, silicon, aluminum, silver, and gold) and two metals with the hexagonal close packing structure (beryllium and magnesium). Our results are compared to available experimental data and previous computational studies. Calculated linear and nonlinear elastic constants are also used in the context of nonlinear elasticity theory to predict values of volume and bulk modulus over an interval of pressures. These predictions are compared to results obtained from density functional theory calculations to assess the reliability of our method.