Theoretical Studies of Non-Crystalline Solids

开发了新的方法来可靠地模拟复杂的和具有重要技术意义的玻璃和非晶态材料。重点是结构建模，原子在材料中的扩散，以及电子性质，包括非晶态环境中的跳跃和输运。这项工作影响了广泛和重要的材料，其应用范围从计算机存储器(固体玻璃硫化物-银电解液)、数字X射线照相术(非晶硫化物)到太阳能光伏(非晶氢化硅)。该奖项涉及非晶态半导体中的结构、扩散原子动力学、电子态及其动力学等基本问题。这些问题包括：创建复杂玻璃的新结构模型的方法，以及对这些模型的彻底分析(拓扑和化学有序的性质，电子和动力学性质)。使用新的技术，我们将确定这些玻璃中的非扩散动力学(这是一个重要的领域，有许多扩散动力学的唯象模型，但很少有原子计算与“现实的”原子间相互作用)。用于模拟扩散动力学的技术是相当新的，并有望从本基金研究的复杂材料获得的经验中发展(一般而言，这种方法与生物物理学中的问题有关，如蛋白质折叠和聚合物中的动力学)。最后，有关电子动力学的工作将为基于跳跃的载流子在玻璃和其他无序材料中的输运提供新的见解。我们还将通过直接模拟来探索热驱动电子跳跃现象：这将为有限温度安德森问题增加重要的新见解。这里进行的研究将纳入PI教授的课程，学生，包括那些来自代表不足的群体的学生，将参与研究。研究结果，特别是原子坐标，将通过互联网获得。还有一些链接指向亚利桑那州坦佩的一家小型初创公司Axon Technologies。开发了新的方法来可靠地模拟复杂的和具有重要技术意义的玻璃和非晶态材料。重点是结构建模，原子在材料中的扩散，以及电子性质，包括非晶态环境中的跳跃和输运。这项工作影响了广泛和重要的材料，其应用范围从计算机存储器(固体玻璃硫化物-银电解液)、数字X射线照相术(非晶硫化物)到太阳能光伏(非晶氢化硅)。在这里进行的研究将纳入国际学生联合会教授的课程，学生，包括那些来自代表人数不足的群体的学生，将参与研究。研究结果，特别是原子坐标，将通过互联网获得。还有一些链接指向亚利桑那州坦佩的一家小型初创公司Axon Technologies。***

New methods are developed to reliably model complex and technologically important glasses and amorphous materials. The focus is on structural modeling, atomic diffusion in the materials, and electronic properties including hopping and transport in non-crystalline environments. This work impacts a broad and important range of materials with applications ranging from computer memories (solid glassy chalcogenide-silver electrolytes), digital x-ray radiography (amorphous chalcogenides) to solar photovoltaics (amorphous silicon hydride). This award addresses fundamental questions concerning structure, diffusive atomic dynamics, and electron states and their dynamics in non-crystalline semiconductors. Among these issues are: methods for creating new structural models for complex glasses, and thorough analysis of these models (the nature of topological and chemical ordering, electronic and dynamical properties). Using novel techniques, we will determine non-diffusive dynamics in these glasses (this is an important area with many phenomenological models of the diffusive dynamics, but few atomistic calculations with "realistic" interatomic interactions). The techniques for modeling diffusive dynamics are quite new, and expected to develop from the experience obtained from the complex materials studied in this grant (in a general way, such methods are relevant to problems in biophysics like protein folding and dynamics in polymers). Finally, the work on electron dynamics will give new insight into hopping-based carrier transport in glasses, and other disordered materials. Also we will explore the phenomenon of thermally driven electron hopping by direct simulation: this will add important new insights to the finite-temperature Anderson problem.The research conducted here will be incorporated into courses taught by the PI and students, including those from underrepresented groups, will participate in the research. Results of the research, atomic coordinates in particular, will be available through the internet. There are also links to a small, startup company, Axon Technologies, in Tempe, AZ. %%%New methods are developed to reliably model complex and technologically important glasses and amorphous materials. The focus is on structural modeling, atomic diffusion in the materials, and electronic properties including hopping and transport in non-crystalline environments. This work impacts a broad and important range of materials with applications ranging from computer memories (solid glassy chalcogenide-silver electrolytes), digital x-ray radiography (amorphous chalcogenides) to solar photovoltaics (amorphous silicon hydride). The research conducted here will be incorporated into courses taught by the PI and students, including those from underrepresented groups, will participate in the research. Results of the research, atomic coordinates in particular, will be available through the internet. There are also links to a small, startup company, Axon Technologies, in Tempe, AZ. ***