Polycrystalline solids can exhibit material properties that differ significantly from those of equivalent single-crystal samples, in part, because of a spontaneous redistribution of mobile point defects into so-called space-charge regions adjacent to grain boundaries. The general analytical form of these space-charge regions is known only in the dilute limit, where defect-defect correlations can be neglected. Using kinetic Monte Carlo simulations of a three-dimensional Coulomb lattice gas, we show that grain boundary space-charge regions in nondilute solid electrolytes exhibit overscreening—damped oscillatory space-charge profiles—and underscreening—decay lengths that are longer than the corresponding Debye length and that increase with increasing defect-defect interaction strength. Overscreening and underscreening are known phenomena in concentrated liquid electrolytes, and the observation of functionally analogous behavior in solid electrolyte space-charge regions suggests that the same underlying physics drives behavior in both classes of systems. We therefore expect theoretical approaches developed to study nondilute liquid electrolytes to be equally applicable to future studies of solid electrolytes.

中文翻译：

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固体电解质晶界空间电荷层中的过筛和欠筛

多晶固体可以表现出与等效单晶样品显着不同的材料特性，部分原因是移动点缺陷自发地重新分布到与晶界相邻的所谓空间电荷区域中。这些空间电荷区的一般分析形式仅在稀极限中已知，其中缺陷-缺陷相关性可以忽略。使用三维库仑晶格气体的动力学蒙特卡罗模拟，我们表明非稀释固体电解质中的晶界空间电荷区域表现出过筛（阻尼振荡空间电荷分布）和筛下 – 衰减长度比相应的德拜长度更长并且随着缺陷-缺陷相互作用强度的增加而增加。过筛和欠筛是浓缩液体电解质中的已知现象，固体电解质空间电荷区域中功能类似行为的观察表明，相同的基础物理驱动了两类系统中的行为。因此，我们期望为研究非稀释液体电解质而开发的理论方法同样适用于未来的固体电解质研究。