Exploring Growth Mechanisms of Nonequilibrium Nanostructured Materials

本项目支持新材料生长机制的理论和计算研究，以及与教育和推广活动的整合。在材料生长或制造过程中，纳米结构的形成和演化是一个重要的现象，它在控制材料的基本性能和技术重要性方面起着关键作用。本研究解决了理解和预测纳米结构材料的生长和自组装的基本挑战，特别是如何有效地解决系统的复杂性，这些系统远非平衡的平静状态，需要一个可以跨越大范围长度尺度的描述，包括跨越长度尺度的相互关联的过程。PI将开发预测建模方法，并进行理论分析和计算机模拟，以研究从这些过程中出现的新型纳米结构的生长和动力学，并预测在各种材料生长或加工条件下薄膜中的新型调制结构。该项目支持研究生的培训和教育，并通过为暑期学校和讲习班开发讲座，为研究界开展更广泛的教育工作。该项目结合了PI在底特律一所少数族裔女子公立学校的STEM教育推广活动。这些活动包括对高中生科学项目的指导和支持，以及对韦恩州立大学教育本科生的培训，以加强对少数民族学生中代表性不足的年轻女性的K-12 STEM教育，以及职前和在职科学教师的专业发展。本项目支持理论和计算研究与教育相结合，为非平衡纳米结构材料的生长和动力学提供系统的研究。该研究解决了理解和预测功能材料系统中纳米结构组装背后的生长机制的基本挑战，特别是对于不平衡的系统，以及由控制材料微观结构和动力学的不同空间尺度之间的耦合效应所控制的系统。本研究的重点是通过三个部分的研究，探索形态和成分均可调制的新型纳米结构：(1)基于相场晶体方法和振幅形式的建模方法的发展，可以桥接介观和微观尺度，并结合系统的弹性和塑性；(2)材料异质外延过程中纳米结构的形成和动力学的研究，特别是由纳米级成分模式或共晶微观结构调制的应变量子点；(3)中观和微观尺度耦合机制的研究。形态和成分的中尺度不稳定性之间的耦合以及中尺度和微观尺度之间的耦合决定了不同的生长模式。全面的研究将进行数值和分析，以确定各种材料的生长机制和实现可控和相干纳米结构的生长条件，并预测异质外延系统中新型的调制结构。本研究的总体目标是促进我们对非平衡态和纳米结构材料系统的结构和成分动力学的理解。该项目还整合了研究生和本科教育的努力，以及为职前和在职科学教师及其高中生的科学项目设计的外展活动，以加强对底特律少数族裔学生中代表性不足的年轻女性的K-12科学教育。

NONTECHNICAL SUMMARYThis project supports theoretical and computational research on the study of novel materials growth mechanisms and the integration with education and outreach activities. An important phenomenon during the materials growth or fabrication process is the formation and evolution of structures at the nanoscale, which plays a pivotal role in controlling material properties that are of fundamental and technological importance. This research addresses a fundamental challenge of understanding and predicting the growth and self-assembly of nanostructured materials, particularly how to effectively tackle the complexity of the systems which are far from the tranquil state of equilibrium and require a description that can span a wide range of length scales and include interconnected processes across length scales. The PI will develop predictive modeling methods and conduct theoretical analyses and computer simulations to investigate the growth and dynamics of novel nanostructures that emerge from these processes, and predict new types of modulated structures in thin films under various material growth or processing conditions.This project supports the training and education of graduate students, and involves the PI's broader education efforts for the research community through lecture development for summer schools and workshops. This project incorporates the PI's outreach activities for STEM education in an all-girls minority public school in Detroit. The activities include the instruction and support of high-school student science projects and the training of Wayne State education undergraduates, to enhance the K-12 STEM education for young women who are underrepresented minority students and the professional development of both pre-service and in-service science teachers.TECHNICAL SUMMARYThis project supports theoretical and computational research integrated with education to provide a systematic study on the growth and dynamics of nonequilibrium nanostructured materials. The research addresses a fundamental challenge of understanding and predicting the growth mechanisms underlying the nanostructure assembly in functional material systems, particularly for systems that are out of equilibrium and governed by effects of coupling among different spatial scales that control material microstructures and dynamics. This research focuses on the exploration of novel nanostructures that are both morphologically and compositionally modulated, through three parts of investigation: (i) the development of modeling approaches based on the phase field crystal method and amplitude formalism, which can bridge mesoscopic and microscopic scales and incorporate system elasticity and plasticity, (ii) the study of nanostructure formation and dynamics during material heteroepitaxy, particularly for strained quantum dots modulated by nanoscale compositional patterns or eutectic microstructures, and (iii) the investigation of coupling mechanisms at meso and micro scales, for the coupling between morphological and compositional meso-scale instabilities and the coupling between meso and micro scales determining different growth modes. Comprehensive studies will be conducted numerically and analytically to identify various material growth mechanisms and the growth conditions for achieving controllable and coherent nanostructures, and predict new types of modulated structures in heteroepitaxial systems. The overall objective of this research is to advance our understanding of both structural and compositional dynamics in nonequilibrium and nanostructured material systems. This project also integrates the efforts of graduate and undergraduate education, and outreach activities designed for pre-service and in-service science teachers and their high-school students' science projects, to enhance K-12 science education for young women in Detroit who are underrepresented minority students.