Diamond-structured grain boundaries (GBs) are important because they have notable effects on the performances of many functional devices. Previous studies have suggested that the most stable structures of some silicon GBs can be obtained by structural reconstruction from some meta-stable GBs explored at 0 K by atomic simulation. While GB reconstruction is possible to enable these meta-stable GBs to exist at elevated temperatures, reports on such behaviors are rare. This work unveiled a non-reported GB reconstruction from two degenerate ground-states of a well-known silicon GB which can be distinguished by an orientational feature of their unit structures. The reconstructing structures were verified stable by density-functional-theory (DFT) simulation. By thermodynamical and kinetical discussion, we have shown that the structural variation of this well-known GB at elevated temperatures is more likely to be dominated by this reconstruction mechanism rather than by transforming to other metastates. Such a reconstruction mechanism allows the whole GB system to be treated as an Ising model with a second-ordered phase transition. By applying harmonic transition state theory, we predicted the possible concentration of the defects induced by reconstruction at elevated temperatures and discussed their effects on the band structure of the GB by DFT simulation. An explanation was made on the cause of the difference between the phase transition behavior of this silicon GB and that of a reported copper GB. Our research made new insights into understanding the behavior of reconstructing interfaces in covalent-bonded crystalline materials.

金刚石结构晶界 (GB) 很重要，因为它们对许多功能器件的性能有显着影响。先前的研究表明，一些硅 GB 的最稳定结构可以通过原子模拟在 0 K 探索的一些亚稳定 GB 的结构重建获得。虽然 GB 重建有可能使这些亚稳态 GB 存在于高温下，但关于此类行为的报告很少见。这项工作揭示了一种未报告的 GB 重建，它来自一个众所周知的硅 GB 的两个退化基态，可以通过它们的单元结构的取向特征来区分。通过密度泛函理论 (DFT) 模拟验证了重建结构的稳定性。通过热力学和动力学讨论，我们已经表明，这个众所周知的 GB 在高温下的结构变化更有可能受这种重建机制的支配，而不是通过转化为其他转移状态。这种重构机制允许将整个 GB 系统视为具有二阶相变的 Ising 模型。通过应用谐波过渡态理论，我们预测了高温下重建引起的缺陷的可能浓度，并通过 DFT 模拟讨论了它们对 GB 能带结构的影响。对该硅 GB 的相变行为与报道的铜 GB 相变行为之间差异的原因进行了解释。我们的研究对理解共价键合晶体材料中重建界面的行为有了新的见解。