论文标题
缺陷传输张量的自动计算和收敛性
Automated calculation and convergence of defect transport tensors
论文作者
论文摘要
缺陷运输是材料科学和催化的关键过程，但是由于迁移机制通常太复杂而无法列举先验，因此计算运输量通常没有融合的量度，需要大量的最终用户干预。这两个瓶颈可防止高通量实现，这对于将原子间相互作用到预测模拟传播模型形式的不确定性必不可少。为了解决这些问题，我们扩展了一个大规模平行的加速采样方案，该方案由贝叶斯估算的状态采样完整性自主控制，以在交换和空间群体对称性下的状态空间上构建原子动力学蒙特卡洛模型。专注于孤立的缺陷，我们得出了用于缺陷传输张量的分析表达式，并通过计算与采样不确定性一致的扩散过程的集合中的kullback-leber差异来提供收敛度量。该方法的自主性和疗效在氧化镁的钨和六角性互化中的表面三聚体中得到了证明，这两种镁都表现出复杂的，相关的迁移机制。
Defect transport is a key process in materials science and catalysis, but as migration mechanisms are often too complex to enumerate a priori, calculation of transport tensors typically have no measure of convergence and require significant end user intervention. These two bottlenecks prevent high-throughput implementations essential to propagate model-form uncertainty from interatomic interactions to predictive simulations. In order to address these issues, we extend a massively parallel accelerated sampling scheme, autonomously controlled by Bayesian estimators of statewise sampling completeness, to build atomistic kinetic Monte Carlo models on a state space irreducible under exchange and space group symmetries. Focusing on isolated defects, we derive analytic expressions for defect transport tensors and provide a convergence metric by calculating the Kullback-Leiber divergence across the ensemble of diffusion processes consistent with the sampling uncertainty. The autonomy and efficacy of the method is demonstrated on surface trimers in tungsten and hexa-interstitials in magnesium oxide, both of which exhibit complex, correlated migration mechanisms.
