The Generalized Cluster Expansion: A Tool for Representing Structure-Property Relationships

广义簇展开：表示结构-性质关系的工具

• 批准号: 0907669
• 负责人: Axel van de Walle
• 金额: $ 30.6万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0907669&HistoricalAwards=false
• 关键词: Generalized; Cluster; Expansion; Tool; Representing

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).TECHNICAL SUMMARYStructure-property relationships have long guided materials discovery and improved our understanding of the mechanisms underlying diverse physical phenomena. This award supports developing a set of theoretical and computational tools to determine and efficiently represent the relationship between the atomic structure of a compound and a given material property. The starting point is the cluster expansion formalism, which can express the relationship between a scalar material property and a crystalline alloy?s atomic configuration. This project generalizes this formalism to tensor-valued and nonuniform/nonisotropic material properties.The resulting generalized cluster expansion coupled with first-principles calculations will be applied in three general areas:(1) Phase field modeling: the generalized cluster expansion can encode the relationship between various phase fields representing the state of order of an alloy and tensorial properties, such as elastic constants or lattice parameters that enter the mesoscopic equation of motion of the simulated system.(2) Automated discovery of atomistic mechanisms: An illustrative application is the determination of the atomic-level origins of specific features in the phonon spectrum through the use of environment-dependent force constants tensors. Here, each term in the generalized cluster expansion would provide independent geometrical insight regarding the mechanisms at work.(3) Materials discovery and/or optimization: The generalized cluster expansion will be used to demonstrate an efficient computational combinatorial screening of a large number of candidate superlattices in search of one with the desired combination of properties relevant for device design.Software tools developed in this project will be included within the Alloy Theoretic Automated Toolkit, a widely used software package that the PI has made available on the world-wide web. This project will promote integration of research and education as well as diversity in science by contributing to the Materials Partnership Program established by Caltech?s Center for the Science and Engineering of Materials which recruits undergraduates from California State University, Los Angeles in collaborative research projects with Caltech.NON-TECHNICAL SUMMARYThis award supports theoretical and computational research that will develop new computational algorithms and tools for determining the relationship between the structure of a specific, possibly candidate, material and its properties. The PI will extend an existing approach to enable inclusion of a larger set of materials properties that enhance the power and utility of the method. The research effort contributes to the effort to discover new materials with desired properties using computation and starting only with the identity of the constituent atoms. This research may lead to the discovery of new materials with desired properties for technological applications, or optimizing the properties of existing materials or materials structures. New materials for optoelectronic devices are a specific focus of this project. Software tools developed in this project will be made available to the broader materials research community and will contribute to its cyberinfrastructure.

该奖项根据 2009 年美国复苏和再投资法案（公法 111-5）提供资金。 技术摘要 结构-属性关系长期以来一直指导着材料发现，并增进了我们对各种物理现象背后机制的理解。该奖项支持开发一套理论和计算工具，以确定并有效地表示化合物的原子结构与给定材料特性之间的关系。起点是簇展开形式主义，它可以表达标量材料属性和晶体合金原子构型之间的关系。该项目将这种形式主义推广到张量值和非均匀/非各向同性材料属性。由此产生的广义簇展开与第一性原理计算相结合将应用于三个一般领域：（1）相场建模：广义簇展开可以编码代表合金有序状态的各种相场和张量属性之间的关系，例如进入合金的弹性常数或晶格参数。 模拟系统的介观运动方程。(2)原子机制的自动发现：一个说明性应用是通过使用与环境相关的力常数张量来确定声子谱中特定特征的原子级起源。在这里，广义簇展开中的每一项都将提供有关工作机制的独立几何见解。(3) 材料发现和/或优化：广义簇展开将用于演示对大量候选超晶格的有效计算组合筛选，以寻找具有与器件设计相关的所需属性组合的超晶格。该项目中开发的软件工具将包含在合金理论自动化中 Toolkit，PI 已在万维网上提供的广泛使用的软件包。该项目将通过为加州理工学院材料科学与工程中心建立的材料合作计划做出贡献，促进研究和教育的整合以及科学的多样性，该计划招募来自加州州立大学洛杉矶分校的本科生与加州理工学院进行合作研究项目。非技术摘要该奖项支持理论和计算研究，这些研究将开发新的计算算法和工具，用于确定材料结构之间的关系。 具体的、可能候选的材料及其属性。 PI 将扩展现有方法，以纳入更多的材料属性，从而增强该方法的功能和实用性。这项研究工作有助于通过计算并从组成原子的身份开始发现具有所需特性的新材料。这项研究可能会发现具有技术应用所需特性的新材料，或优化现有材料或材料结构的特性。用于光电器件的新材料是该项目的具体重点。 该项目开发的软件工具将提供给更广泛的材料研究界，并将为其网络基础设施做出贡献。