Abstract Using the path-integral Monte Carlo method, we investigate the quantum effects on the elastic constants C 11 , C 12 , and C 44 of the diamond crystal in a wide temperature range at ambient pressure. The Tersoff potential is used to describe the interatomic interactions and the elastic constants are determined by a direct method derived from the stress-strain curve. We find that the elastic constants C 11 and C 44 behave as a quadratic function of temperature at low temperatures and C 12 is practically a constant being independent of temperature. The quantum effects are significant at low temperatures up to about 1000 K. The quantitative differences between the PIMC calculations and the experimental measurements of the elastic constants C 11 , C 12 , and C 44 at low temperatures are about 3 % , 17 % , and 9 % , respectively. Using the obtained elastic constants, we also estimate the bulk modulus B, anisotropic factor A, Cauchy pressure P Cauchy , and Poisson ratio ν of the diamond crystal.

中文翻译：

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通过路径积分蒙特卡罗模拟对金刚石弹性常数的量子效应

摘要 使用路径积分蒙特卡罗方法，我们研究了在宽温度范围和环境压力下对金刚石晶体弹性常数 C 11 、C 12 和 C 44 的量子效应。Tersoff 势用于描述原子间相互作用，弹性常数由从应力-应变曲线导出的直接方法确定。我们发现弹性常数 C 11 和 C 44 在低温下表现为温度的二次函数，而 C 12 实际上是一个与温度无关的常数。量子效应在高达约 1000 K 的低温下非常显着。 PIMC 计算与低温下弹性常数 C 11 、C 12 和 C 44 的实验测量值之间的数量差异约为 3 % 、 17 % 和9%，分别。