ABSTRACT

Silicon carbide is an important material with applications in numerous domains, but for which our knowledge of basic properties like elastic constants is surprisingly limited. Although several density functional theory calculations have been reported, those are usually not accurate enough, with a sizeable dispersion of published values. A heuristic method is proposed here, allowing for largely reducing the uncertainty. It is based on the use of a weighted average of errors for two reference materials, Si and C. It is demonstrated that this method is effective for physical properties like the lattice parameter and the bulk modulus. It is then used for determining the full sets of elastic constants for the 3C, 2H, 4H, and 6H silicon carbide polytypes.

摘要

碳化硅是一种重要的材料，在许多领域都有应用，但对于我们这些基本属性（如弹性常数）的知识却令人惊讶地受到限制。尽管已报告了几种密度泛函理论计算，但这些计算通常不够准确，而且发布的值存在较大差异。本文提出了一种启发式方法，可以大大减少不确定性。它基于对两种参考材料Si和C的误差加权平均值的使用。证明了该方法对于诸如晶格参数和体积模量的物理性质有效。然后将其用于确定3C，2H，4H和6H碳化硅多型体的全套弹性常数。