AI 中文总结
本研究通过路径积分分子动力学模拟，揭示硅空位及核量子效应会显著改变3C-SiC的弹性质与力学稳定域，为极端环境应用及量子技术提供微观见解。
AI 中文摘要
本研究探究硅空位如何改变立方3C-SiC的弹性响应与力学稳定性。研究采用基于高效紧束缚哈密顿量的路径积分分子动力学模拟，包含经典原子核极限，其精度通过密度泛函理论计算验证。该框架可定量评估由零点运动产生的核量子效应。在涵盖拉伸与压缩 regime 的宽温度及流体静压力范围内，与无缺陷晶体相比，硅空位会显著重整化弹性常数$C_{11}$、$C_{12}$、$C_{44}$以及体积模量。纳入核量子运动会使这些弹性质进一步软化，尤其在低温下，表明量子涨落对含缺陷SiC的力学响应有可测量贡献。空位还会影响3C-SiC的力学稳定域，对于晶格位点缺陷浓度为0.016的情况，将最大可持续拉伸压力降低约4 GPa。这些结果揭示了点缺陷与量子晶格涨落在决定SiC弹性行为方面的相互作用，为极端环境结构应用及基于缺陷的量子技术提供了相关微观见解。
英文摘要
We investigate how silicon vacancies modify the elastic response and mechanical stability of cubic 3C-SiC. Our approach employs path-integral molecular dynamics simulations, including the classical-nuclei limit, based on an efficient tight-binding Hamiltonian, whose accuracy is validated against density-functional-theory calculations. This framework enables a quantitative assessment of nuclear quantum effects arising from zero-point motion. Across a broad range of temperatures and hydrostatic pressures, spanning both tensile and compressive regimes, silicon vacancies are found to substantially renormalize the elastic constants $C_{11}$, $C_{12}$, and $C_{44}$, as well as the bulk modulus, relative to the defect-free crystal. Inclusion of nuclear quantum motion produces an additional softening of these elastic properties, particularly at low temperatures, demonstrating that quantum fluctuations make a measurable contribution to the mechanical response of defective SiC. Vacancies also affect the mechanical stability domain of 3C-SiC, lowering the maximum sustainable tensile pressure by approximately 4 GPa for a defect concentration of 0.016 per lattice site. These results reveal an interplay between point defects and quantum lattice fluctuations in determining the elastic behavior of SiC, providing microscopic insight relevant for both extreme-environment structural applications and defect-based quantum technologies.
Comments19 pages, 12 figures
Journal refPhys. Rev.B 114, 014109 (2026)
