Abstract We conducted DFT calculations and molecular dynamics simulation to investigate the effect of small (less than 1%) concentrations of As-antisite (AsGa) defect to the GaAs bulk lattice. We found that the lattice does not expand nor contract at 0.39% and 0.78% defect concentrations but retains the equilibrium lattice parameter of the GaAs. This clarifies the experimental observations of a plateau-type relationship of lattice expansion and defect concentration in the regime of very low AsGa content. We also found that the defect prefers clustered over dispersed structure. Using molecular dynamics simulations, we observed that such preservation of lattice parameter holds true even at 300 K. Also, interestingly, we found that the mid-gap state starts to appear at 0.78% defect concentration, while GaAs bulk with 0.39% AsGa mimics the semiconducting property of undefected GaAs.

中文翻译：

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GaAs 体晶格真的会因为低浓度区的缺陷而膨胀吗？

摘要 我们进行了 DFT 计算和分子动力学模拟，以研究小浓度（小于 1%）的 As-antisite (AsGa) 缺陷对 GaAs 体晶格的影响。我们发现晶格在 0.39% 和 0.78% 的缺陷浓度下既不膨胀也不收缩，但保留了 GaAs 的平衡晶格参数。这澄清了在极低 AsGa 含量范围内晶格膨胀和缺陷浓度的平台型关系的实验观察结果。我们还发现缺陷更喜欢聚集而不是分散结构。使用分子动力学模拟，我们观察到这种晶格参数的保持即使在 300 K 下也是如此。此外，有趣的是，我们发现中带隙状态开始出现在 0.78% 的缺陷浓度，而 GaAs 体积为 0。