Large Scale Simulations and Local Analysis of Si-based Materials to Study their Energetics, Bonding, and Structural Properties

对硅基材料进行大规模模拟和局部分析，以研究其能量、键合和结构特性

• 批准号: 9802274
• 负责人: Chakram Jayanthi
• 金额: $ 29万
• 依托单位: University of Louisville Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-15 至 2001-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9802274&HistoricalAwards=false
• 关键词: Large; Scale; Simulations; Local; Analysis

9802274 Jayanthi This is a theoretical research project, largely computational, involving the University of Louisville and Oak Ridge National Laboratory. There is also experimental collaboration with the University of Wisconsin. The central objective is to perform large scale simulations based on the order-N O(N) non-orthogonal tight-binding molecular dynamics (NOTB-MD) to predict accurately the structural, electronic, and bonding properties of Si-based materials. Very recently an O(N) technique for the calculation of both total energy as well as atomic forces has been developed by two of the PI's in the context of a NOTB Hamiltonian. The importance of the O(N) technique is that it overcomes the bottleneck present in the conventional total energy and atomic force calculations by reducing the scaling of computational time from N3 to N, where N denotes the size of the system. The advantage of NOTB Hamiltonian is that it incorporates a quantum mechanical description of the electronic structure and it is best suited for situations with arbitrary coordination encountered in MD simulations. Hence, the O(N) NOTB-MD scheme provides an excellent means to investigate systems with realistic sizes that are currently outside the scope of first-principles molecular dynamics simulations. Furthermore, using innovative local measures and the method of real space Green's function in conjunction with the O(N) NOTB-MD technique, a powerful tool is now in place to analyze the vast amount of information obtained from a MD simulation. The twin theme of performing large scale simulations, and predicting properties accurately at the microscopic level, is one of the unique features of this research. The research is comprised of four projects. The first focuses on the initial stages of growth of Si and Ge depositions on a Si(100) surface. The second is concerned with the study of the onset of the transition from a two- dimensional to three-dimensional growth for Gen films d eposited on the Si(001) substrate. In project three, equilibrium and electronic structures of Si nanoparticles from a few hundred to a few thousand atoms will be investigated with the aim of understanding the effect of quantum confinement on the properties of these nanosystems. Finally, project four looks at issues related to the fabrication of nanoheterostructures (SixGe1-x) and the effect of strain on their properties will be explored. The scientific outcome of this study is expected to lead to the understanding of the link between the adsorption of monomers and the formation of growth structures in Si and Ge depositions on the Si(100) substrate, the formation of islands, alloy ordering and surface segregation, equilibrium shape of nanoparticles, the effect of quantum confinement on the properties of Si nanoparticles, etc. %%% This is a theoretical research project, largely computational, involving the University of Louisville and Oak Ridge National Laboratory. There is also experimental collaboration with the University of Wisconsin. The central objective is to perform large scale simulations to predict accurately the structural, electronic, and bonding properties of silicon-based materials. The twin theme of performing large scale simulations, and predicting properties accurately at the microscopic level, is one of the unique features of this research. The scientific outcome of this study is expected to lead to the understanding of the link between the adsorption of monomers and the formation of growth structures in silicon and germanium depositions on the silicon substrate, the formation of islands, alloy ordering and surface segregation, equilibrium shape of nanoparticles, the effect of quantum confinement on the properties of silicon nanoparticles, etc. Research results will be of great fundamental interest and will find broad application in the microelectronic industry. ***

9802274 Jayanthi这是一个理论研究项目，主要是计算性的，涉及路易斯维尔大学和橡树岭国家实验室。此外，还与威斯康星大学进行了实验性合作。中心目标是基于-N O(N)非正交紧束缚分子动力学(NOTB-MD)进行大规模模拟，以准确地预测硅基材料的结构、电子和成键性质。最近，两个PI在NOTB哈密顿量的背景下发展了一种O(N)技术，用于计算总能量和原子力。O(N)技术的重要性在于它克服了传统总能量和原子力计算中存在的瓶颈，将计算时间的标度从N3减少到N，其中N表示系统的大小。NOTB哈密顿量的优点是它包含了对电子结构的量子力学描述，并且最适合于MD模拟中遇到的任意配位的情况。因此，O(N)NOTB-MD方案为研究目前在第一性原理分子动力学模拟范围之外的具有实际大小的系统提供了一个很好的手段。此外，使用创新的局部措施和实空间格林函数的方法与O(N)NOTB-MD技术相结合，现在已经有了一个强大的工具来分析从MD模拟获得的大量信息。执行大规模模拟和在微观层面上准确预测特性这两个主题是这项研究的独特之处之一。这项研究包括四个项目。第一部分主要研究了Si和Ge在Si(100)表面上生长的初期阶段。第二部分是关于在Si(001)衬底上生长的GeN薄膜从二维到三维转变的研究。在第三个项目中，我们将研究从几百个原子到几千个原子的硅纳米粒子的平衡和电子结构，以了解量子限制对这些纳米系统性质的影响。最后，项目四着眼于与纳米异质结构(SixGe1-x)的制备有关的问题，并将探索应变对其性能的影响。这项研究的科学成果有望有助于理解单体吸附与Si(100)衬底上Si和Ge沉积中生长结构的形成、孤岛的形成、合金有序和表面偏析、纳米颗粒的平衡形状、量子限制对纳米硅颗粒性能的影响等之间的联系。%这是一个理论研究项目，主要是计算的，涉及路易斯维尔大学和橡树岭国家实验室。此外，还与威斯康星大学进行了实验性合作。中心目标是进行大规模模拟，以准确预测硅基材料的结构、电子和成键性能。执行大规模模拟和在微观层面上准确预测特性这两个主题是这项研究的独特之处之一。这项研究的科学成果有望有助于理解单体吸附与硅中生长结构的形成以及硅衬底上锗沉积之间的联系，岛的形成，合金有序和表面偏析，纳米粒子的平衡形状，量子限制对纳米硅粒子性能的影响等。研究成果将具有重要的基础性意义，并将在微电子工业中得到广泛应用。***