Modeling complex properties of material interfaces: from quantum and atomic to macroscopic scales

这项研究将提出一种从原子和量子力学水平出发的计算方法，并通过推导出只涉及材料界面附近自由度的简化模型，弥合原子模型和宏观性质之间的显著差距。这最终允许基于第一原理在更大的尺度上研究材料的集体性质。研究结果将被纳入研究生课程和本科生暑期研究计划。材料特性主要由潜在的微观结构决定。几何界面，如晶界和沉淀物，代表了一些最有趣和最重要的材料结构。该项目的目标是开发高精度的计算工具，用于模拟和理解界面在材料特性中的作用。现代计算能力的出现改变了许多材料建模工作的定性性质。特别是，依赖原子尺度相互作用的计算机模型已经成为一种流行的方法。然而，在大多数情况下，直接原子模拟仍然局限于具有简单几何结构的小系统，并且它们无法处理它们应该描述的系统的现实。通过适当的数学归约方法，这项研究将能够在保持原子和电子水平描述的准确性的同时，实现大规模的材料模拟。

This research will advance a computational method that starts at atomic and quantum-mechanical level, and bridges the significant gap between atomistic models and macroscopic properties by deriving a reduced model that only involves the degrees of freedom near the material interfaces. This ultimately permits the study of collective properties of materials on much larger scales based on first principle. Results of the research will be incorporated into graduate courses and undergraduate summer research programs.Material properties are mostly determined by the underlying micro-structures. Geometric interfaces, such as grain boundaries and precipitates, represent some of the most interesting and important material structures. The goal of this project is to develop highly accurate computational tools for simulating and understanding the roles of interfaces in material properties. The advent of modern computing capability has changed the qualitative nature of much of the material modeling effort. In particular, computer models that rely on atomic scale interactions have emerged as a popular approach. In most cases, however, direct atomistic simulations are still limited to small systems with simple geometry, and they are unable to deal with the realities of the systems that they are supposed to describe. With an appropriate mathematical reduction method, this research will enable large-scale material simulations while still retaining the accuracy of atomic and electronic level descriptions.