Collaborative Research: Ab Initio Computation of Phonon Thermal Transport in Crystalline and Disordered Materials

合作研究：晶体和无序材料中声子热传输的从头算

• 批准号: 1066634
• 负责人: David Broido
• 金额: $ 12.62万
• 依托单位: Boston College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1066634&HistoricalAwards=false
• 关键词: Collaborative; Research; Ab; Initio; Computation

1066634BroidoThe lattice thermal conductivity is a fundamental thermal transport parameter that determines the utility of materials for specific thermal management applications. Accurate theoretical modeling of the lattice thermal conductivity is essential to numerous fields including microelectronics cooling, thermoelectrics, and even planetary science. The goal of this collaborative research effort will be to implement a theoretical approach to calculate the lattice thermal conductivity of crystalline and alloyed materials from first principles. A central feature of this approach is that it has no adjustable parameters.The focus at the Boston College site will be in using an exact numerical solution of the phonon Boltzmann equation to calculate the lattice thermal conductivity. The materials to be studied in this project include lead chalcogenides, I-V-VI2 semiconductors, and nanoparticle-in-alloy-structures. For nanostructured systems, such as the nanoparticles in alloys, a Non-Equilibrium Green?s Function approach will be implemented. The critical inputs for the transport modeling will come from harmonic and, where necessary, anharmonic interatomic force constants, whose calculation will be the focus of the Cornell site.The first principles approach has already demonstrated excellent agreement with measured high thermal conductivities of group IV semiconductors. The materials to be studied in this project are unified by their exceptionally low thermal conductivities and therefore provide an excellent test of the robustness of the theory. The measured thermal properties of many of these materials are well characterized and will provide an useful check of our calculated adjustable parameter-free results. Good agreement with measured data would further validate the predictive capability of this state-of-the-art theory in studying and understanding thermal transport and the lattice thermal conductivity in a wide range of materials for many thermal management applications.Intellectual merit: Current theories of the lattice thermal conductivity of materials are typically based on either highly parameterized relaxation time approximations or on purely classical molecular dynamics calculations. The rigorous first principles theory proposed here has no adjustable parameters and incorporates fully the quantum mechanical phonon scattering processes. It therefore could provide currently unavailable predictive power to support ongoing and future experimental studies of thermal transport in materials, as well as contributing to the development of new highly efficient materials engineered for desired thermal management applications.Broader impacts: The project will provide training for one postdoctoral researcher and one doctoral graduate student. In addition, several undergraduates including those from underrepresented groups will participate through NSF REU programs at both Boston College and Cornell sites. The computational tools to be developed during this project will be incorporated into the publicly available computing library of the Cornell Nanoscale Science and Technology Facility (CNF). The activity will also benefit society by aiding in the development of new materials with desired thermal transport properties. This will facilitate technological breakthroughs that may lead to the next generation of thermoelectric materials, thermal barrier coating materials, and thermal interface materials.

1066634 Broido晶格热导率是一个基本的热传输参数，它决定了材料在特定热管理应用中的效用。晶格热导率的精确理论建模对于包括微电子冷却、热电甚至行星科学在内的许多领域都是必不可少的。 这项合作研究工作的目标将是实施一种理论方法，从第一原理计算晶体和合金材料的晶格热导率。这种方法的一个主要特点是它没有可调参数。波士顿学院的重点将是使用声子玻尔兹曼方程的精确数值解来计算晶格热导率。 在这个项目中要研究的材料包括铅硫族化物，I-V-VI 2半导体和纳米颗粒合金结构。 对于纳米结构体系，如合金中的纳米颗粒，非平衡绿色？的功能方法将被实施。 输运模型的关键输入将来自谐波，必要时，非谐波原子间力常数，其计算将是康奈尔网站的重点。第一性原理方法已经证明了与测量的IV族半导体的高热导率非常一致。在这个项目中要研究的材料是统一的，其异常低的热导率，因此提供了一个很好的测试理论的鲁棒性。 许多这些材料的测量的热性能的特点，并将提供一个有用的检查我们计算的可调参数的结果。与测量数据的良好一致性将进一步验证这一最先进理论在研究和理解许多热管理应用中各种材料的热输运和晶格热导率方面的预测能力。目前材料晶格热导率的理论通常是基于高度参数化的弛豫时间近似或基于纯经典的分子动力学模型。动力学计算这里提出的严格的第一性原理理论没有可调的参数，并充分纳入了量子力学声子散射过程。因此，它可以提供目前无法提供的预测能力，以支持正在进行的和未来的材料热传输实验研究，以及有助于开发新的高效材料，用于所需的热管理应用。更广泛的影响：该项目将为一名博士后研究员和一名博士研究生提供培训。 此外，一些本科生，包括那些来自代表性不足的群体将通过NSF REU计划在波士顿学院和康奈尔大学的网站参加。 该项目期间开发的计算工具将被纳入康奈尔纳米科学技术设施（CNF）的公共计算库。 该活动还将通过帮助开发具有所需热传输特性的新材料来造福社会。这将促进技术突破，可能导致下一代热电材料，热障涂层材料和热界面材料。