A topological model for defects and interfaces in complex crystal structures
A topological model for defects and interfaces in complex crystal structures
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DOI：
10.2138/am-2019-6892
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发表时间：
2019-07-01
影响因子：
3.1
通讯作者：
Hirth, Greg
中科院分区：
文献类型：
--
作者：
Hirth, J. P.;Wang, Jian;Hirth, Greg
针对某些矿物复杂的晶体结构特征，提出了一种拓扑模型(TM)。我们介绍了一种简单的方法来应用TM来表征这些复杂材料中的缺陷。具体地说，我们说明了每个具有包含多个原子的主题的结构基团如何提供晶格和结构，这些晶格和结构对于描述界面中的位错和脱节很有用。还描述了用于确定伴随断开运动的洗牌的简化方法。我们说明了钠长石中孪生的模型，因为它可能在脆塑性转变附近的条件下约束地壳的流变性，而斜长石是常见岩石类型的主要成分。虽然在地壳岩石中经常观察到斜长石中的变形孪晶，但对它们形成的应力状态的解释并未取得进展。结构群的概念使得分析复杂矿物中的孪生过程变得更容易，并明确地预测了变形孪晶的界面结构。
A topological model (TM) is presented for the complex crystal structures characteristic of some minerals. We introduce a tractable method for applying the TM to characterize defects in these complex materials. Specifically, we illustrate how structural groups, each with a motif containing multiple atoms, provide lattices and structures that are useful in describing dislocations and disconnections in interfaces. Simplified methods for determining the shuffles that accompany disconnection motion are also described. We illustrate the model for twinning in albite owing to its potential application for constraining the rheological properties of the crust at conditions near the brittle-plastic transition, where plagioclase is a major constituent of common rock types. While deformation twins in plagioclase are often observed in crustal rocks, the interpretation of the stress states at which they form has not advanced. The concept of structural groups makes an analysis of the twinning process easier in complex minerals and explicitly predicts the interface structure of the deformation twins.