Collaborative Research: First-Principles Calculations of Phonon Thermal Transport in Bulk and Nanostructured Materials

主要研究员：David Broido，1 Natalio Mingo，2和Derek stewart。2加州大学圣克鲁斯分校；3康奈尔大学。提案题目：合作研究：块状和纳米结构材料中声子热输运的第一性原理计算这项合作工作的研究目标是开发一种理论方法，从第一性原理来描述通过块状和纳米结构材料的热输运。这种方法的一个主要特点是它没有可调整的参数。这将允许研究和理解声子热输运和晶格热导率在大量块状半导体以及新型纳米级系统。待研究的系统包括：硅、锗和砷化镓等块状晶体；纳米结构系统，如量子阱和量子线超晶格，具有显著界面电阻的结构，单层和多层薄膜，纳米线和纳米管中的缺陷。目前用于模拟绝缘和半导体材料中的热输运的方法通常要么基于高度参数化的松弛时间近似，要么基于纯粹经典的分子动力学计算。这里要发展的严格的第一原理理论没有可调节的参数，并充分结合了量子力学声子散射过程。因此，它将提供预测能力，以支持正在进行的和未来的纳米材料热传输实验研究，以及为特定应用的新型纳米材料的开发做出贡献。该项目为期三年，将培养1名博士后研究员和1名博士研究生。此外，本科生将通过美国国家科学基金会在波士顿学院和康奈尔大学的本科生研究经验项目参与该项目。在此项目中开发的计算工具将集成到一套免费的声子热输运工具中，该工具将成为康奈尔纳米科学与技术设施（CNF）建立的计算库的一部分。这些计算工具将可供任何研究人员使用。这项研究计划将有助于开发具有理想热传输性能的新材料。这将促进下一代热电材料、热障涂层材料和热界面材料在热管理方面的技术突破。

Principal Investigators: David Broido,1 Natalio Mingo,2 and Derek Stewart.3Affiliation: 1Boston College; 2University of California, Santa Cruz; 3Cornell University.Proposal Title: Collaborative Research: First-Principles Calculations of Phonon Thermal Transport in Bulk and Nanostructured MaterialsThe research objective of this collaborative effort is to develop a theoretical approach to describe thermal transport through bulk and nanostructured materials from first principles. A central feature of this approach is that it has no adjustable parameters. This will allow the study and understanding of phonon thermal transport and lattice thermal conductivity in a host of bulk semiconductors as well as in novel nanoscale systems. Systems to be investigated include: Bulk crystals such as silicon, germanium and gallium arsenide; nanostructured systems such as quantum well and quantum wire superlattices, structures with significance interface resistance, single and multilayer thin films, defects in nanowires and nanotubes.Intellectual Merit Current approaches to model thermal transport in insulating and semiconducting materials are typically based on either highly parameterized relaxation-time approximations or on purely classical molecular dynamics calculations. The rigorous first principles theory to be developed here has no adjustable parameters and incorporates fully the quantum mechanical phonon scattering processes. It will therefore provide predictive power to support ongoing and future experimental studies of thermal transport in nanomaterials, as well as contributing to the development of new nanomaterials engineered for specific applications. Broader Impacts This three-year project will provide training for one postdoctoral researcher and one doctoral graduate student. In addition, undergraduate students will participate in this project through NSF Research Experience for Undergraduates programs at the Boston College and Cornell sites. Computational tools developed during this project will be integrated into a free set of phonon thermal transport tools that will become part of the computing library established at the Cornell Nanoscale Science and Technology Facility (CNF). These computational tools will be available for use by any researcher. This research program will contribute to the development of new materials with desired thermal transport properties. This will facilitate technological breakthroughs in thermal management for the next generation of thermoelectric materials, thermal barrier coating materials, and thermal interface materials.