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arXiv 2302.08754cond-mat.mtrl-sci
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分子计算中的解析弹性常数:有限应变、非仿射位移与多体原子间势

Analytic elastic constants in molecular calculations: Finite strain, non-affine displacements, and many-body interatomic potentials

Jan Grießer, Lucas Frérot, Jonas A. Oldenstaedt, Martin H. Müser, Lars Pastewka

AI总结:

本文重新审视零温度有限应变弹性常数理论,扩展以考虑非仿射位移,给出二体及多体原子间势的势能二阶导数解析表达式,并分析了硅、碳化硅和二氧化硅在静水压缩与膨胀下的弹性常数及多轴应力对晶格稳定性的影响。

摘要:

弹性常数是固体材料最基本且最重要的性质之一,因此在实验和模拟中常被表征。尽管概念简单,但弹性常数的处理因两个尚未被同时讨论的因素而复杂化:有限应变和非仿射内部位移。本文重新审视了零温度、有限应变弹性常数背后的理论,并将其扩展以明确考虑非仿射位移。我们进一步针对二体和一般多体原子间势(如团簇势和经验键序势),给出了势能二阶导数的解析表达式。具体而言,我们重新考察了硅、碳化硅和二氧化硅在静水压缩与膨胀下的弹性常数。基于现有及新结果,我们概述了多轴应力状态(相对于体积变形)对其晶格稳定性极限的影响。

英文摘要:

Elastic constants are among the most fundamental and important properties of solid materials, which is why they are routinely characterized in both experiments and simulations. While conceptually simple, the treatment of elastic constants is complicated by two factors not yet having been concurrently discussed: finite-strain and non-affine, internal displacements. Here, we revisit the theory behind zero-temperature, finite-strain elastic constants and extend it to explicitly consider non-affine displacements. We further present analytical expressions for second-order derivatives of the potential energy for two-body and generic many-body interatomic potentials, such as cluster and empirical bond-order potentials. Specifically, we revisit the elastic constants of silicon, silicon carbide and silicon dioxide under hydrostatic compression and dilatation. Based on existing and new results, we outline the effect of multiaxial stress states as opposed to volumetric deformation on the limits of stability of their crystalline lattices.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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