CAREER: Genetic Approaches to Quantum Mechanics Predictions of Materials Structures

技术综述：该职业奖支持旨在推进合理材料设计的计算和理论研究和教育。PI旨在开发新的计算工具来预测和表征材料的晶体结构，这是材料科学最基本的问题之一，并研究对现代技术具有战略重要性的合金中的低温化合物。虽然合金相图比稳定化合物包含更多的信息，但任何合理的理论材料开发都始于对“可用的”稳定结构的了解。二元相图的实验研究由来已久，但在重要体系中是否存在只有在低温下才稳定的相，这是因为形成这种相需要很长的保持时间。常规的实验方法无法找到这样的低温相，但计算技术很好地适用于预测它们的组成、结构和稳定性。晶体结构的预测通常采用直接模拟的方法。然而，使用这些方法不可能对所有可能的原子构型进行全局优化，因此，只能对可能结构的一小部分进行采样。这项研究用可以代表更广泛的结构和遗传算法的方法来解决这个问题。这项研究的两个目标是：(1)基于作用于局部原子环境的遗传算法，发展合金中化合物的从头算预测技术；(2)使用这些方法来识别具有战略应用的合金中新的金属间化合物结构，例如汽车和航空航天材料、海洋结构应用、纳米技术、医疗应用、催化、教育活动包括招收残疾学生和来自代表性不足人群的学生，并让他们参与研究。PI将与杜克大学的其他教员合作，开设两门课程，涵盖电子结构、配体、合金和化合物理论，使高年级本科生和一年级研究生接触材料设计所需的概念和技术，并培养精通这一新方法的不同学生队伍。虽然已经改善了将残疾人与正常大学生活分开的“建筑障碍”，但仍然存在相当大的障碍，阻碍了残疾学生的接受和融入。PI的目标是在每一年的资助中为听力障碍学生提供暑期研究体验，以鼓励更多的交流和互动，并克服障碍。非技术总结：这个职业奖项支持旨在推进合理材料设计的计算和理论研究和教育。PI将开发新的计算工具，旨在提高仅从组成原子开始预测晶体材料结构的能力。PI的方法将使用一种受生物进化启发的算法来探索比传统方法可以包括的更大的候选结构集。PI计划应用这些方法来加强我们对现有材料的了解，这些材料特别有希望应用于各种应用，包括汽车和航空航天材料(强轻质镁合金)、海洋结构应用(新型钛合金)、纳米技术(用于纳米管生长的金属纳米颗粒)、医疗应用(钽基植入物合金)、催化(铂族纳米颗粒的相稳定性)和能量转换(燃料电池合金)。教育部分包括招收残疾学生和来自代表性不足人群的学生，并让他们参与研究。PI将与杜克大学的其他教员合作，开设两门课程，涵盖电子结构、配体、合金和化合物理论，使高年级本科生和一年级研究生接触材料设计所需的概念和技术，并培养精通这一新方法的不同学生队伍。虽然已经改善了将残疾人与正常大学生活分开的“建筑障碍”，但仍然存在相当大的障碍，阻碍了残疾学生的接受和融入。PI的目标是在每一年的资助中为听障学生提供暑期研究体验，以鼓励更多的交流和互动，并克服障碍。

TECHNICAL SUMMARY:This CAREER award supports computational and theoretical research and education aimed at advancing rational materials design. The PI aims to develop new computational tools for the prediction and characterization of crystal structure of materials, one of the most fundamental problems of materials science, and to investigate low-temperature compounds in alloys of strategic importance for modern technology. Although phase diagrams of alloys contain more information than the stable compounds, any rational theoretical material development begins from the knowledge of the "available" stable structures. Binary phase diagrams have long been studied experimentally, but the existence of phases stable only at low temperature in important systems remains relatively unexplored due to the very long holding times needed to form such phases. Normal experimental methods fail to find such low temperature phases, but computational techniques are well adapted to the prediction of their compositions, structures, and stabilities. The prediction of crystal structures has usually been approached by direct simulation methods. However, a global optimization over all possible atomic configurations is not possible with these methods, and so, only a small subset of possible structures can be sampled. This research approaches the problem with methods that can represent a wider range of structures and genetic algorithms. Local atomic environments are considered as building blocks of structure prototypes, and genetic recombination and mutation concepts are transferred to alloy theory, for the purpose of creating algorithms for global minimization of configuration energies.The two goals of the proposed research, related to alloy theory and characterization are (1) developing techniques for ab initio prediction of compounds in alloys, based on genetic algorithms acting on local atomic environments, and (2) using these methods to identify novel intermetallic compounds structures in alloys with strategic applications, such as automotive and aerospace materials, marine structural applications, nanotechnology, medical applications, catalysis, and energy conversion.The educational activity includes recruiting students with disabilities and students from underrepresented populations and involving them in the research. The PI, in collaboration with other faculty at Duke University, will establish two courses covering the subjects of electronic structure, ligand, alloys and compounds theory which will expose senior undergraduate students and first year graduate students to concepts and techniques necessary for materials design, and educate a diverse cadre of students well versed in this new methodology. While improvements on the "architectural barriers" that separate persons with disabilities from regular university life have been made, there still exists a considerable barrier that prevents the acceptance and inclusion of students with disabilities. The PI aims to provide a summer research experience for a hearing impaired student in each year of funding, to encourage greater interchange and interaction, and overcome barriers.NON-TECHNICAL SUMMARY:This CAREER award supports computational and theoretical research and education aimed at advancing rational materials design. The PI will develop new computational tools with aim of advancing the ability to predict the structure of crystalline materials starting from only the constituent atoms. The PI's methods will use an algorithm inspired by biological evolution to explore a much larger set of candidate structures than traditional methods can include. The PI plans to apply these methods to enhance our understanding of existing materials that are particularly promising for various applications, including automotive and aerospace materials (strong lightweight magnesium alloys), marine structural applications (novel titanium alloys), nanotechnology (metallic nanoparticles for nanotubes growth), medical applications (tantalum based implants alloys), catalysis (phase stability of platinum-group nanoparticles), and energy conversion (alloys for fuel cells).The education component includes recruiting students with disabilities and students from underrepresented populations and involving them in the research. The PI, in collaboration with other faculty at Duke University, will establish two courses covering the subjects of electronic structure, ligand, alloys and compounds theory which will expose senior undergraduate students and first year graduate students to concepts and techniques necessary for materials design, and educate a diverse cadre of students well versed in this new methodology. While improvements on the "architectural barriers" that separate persons with disabilities from regular university life have been made, there still exists a considerable barrier that prevents the acceptance and inclusion of students with disabilities. The PI aims to provide a summer research experience for a hearing impaired student in each year of funding, to encourage greater interchange and interaction, and overcome barriers.