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: 1066406
• 负责人: Derek Stewart
• 金额: $ 19.94万
• 依托单位: Cornell University
• 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 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1066406&HistoricalAwards=false
• 关键词: Collaborative; Research; Ab; Initio; Computation

1066406StewartThe 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 between Boston College and Cornell University 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 Cornell site will focus on calculating ab initio harmonic and, where required, anharmonic interatomic force constants (IFCs) for the materials and structures to be investigated. These calculations will be based on density functional perturbation theory. The IFCs are required inputs for phonon dispersions, phonon density of states, and phonon thermal transport calculations from which the lattice thermal conductivity is obtained. The materials to be studied in this project include lead chalcogenides, I-V-VI2 semiconductors, and nanoparticle-in-alloy-structures.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 important 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 at Cornell University and one doctoral graduate student at Boston College. In addition, several undergraduates including those from underrepresented groups will participate through NSF REU programs at both the 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.

[66406stewart]晶格导热系数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、热电学甚至行星科学在内的许多领域都是必不可少的。波士顿学院和康奈尔大学之间的这项合作研究的目标是实施一种理论方法，从第一性原理计算晶体和合金材料的晶格导热系数。这种方法的一个主要特点是它没有可调整的参数。康奈尔网站将重点计算从头开始谐波，并在需要时，非谐波原子间力常数（IFCs）的材料和结构进行研究。这些计算将基于密度泛函摄动理论。IFCs是声子色散、声子态密度和声子热输运计算所需的输入，从这些计算中可以获得晶格热导率。本项目拟研究的材料包括硫族铅、I-V-VI2半导体和纳米颗粒-合金结构。第一原理方法已经证明与测量的IV族半导体的高导热性非常吻合。在这个项目中要研究的材料是统一的，它们的异常低的热导率，因此提供了一个很好的测试理论的稳健性。许多这些材料的测量热性能都得到了很好的表征，并将为我们计算的可调无参数结果提供重要的检查。与测量数据的良好一致性将进一步验证这一最先进的理论在研究和理解热传输和晶格热导率方面的预测能力，这些理论适用于许多热管理应用。智力优势：目前材料晶格热导率的理论通常是基于高度参数化的松弛时间近似或纯粹经典的分子动力学计算。本文提出的严格的第一性原理理论没有可调参数，并充分结合了量子力学声子散射过程。因此，它可以提供目前无法获得的预测能力，以支持正在进行和未来的材料热传输实验研究，并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：该项目将为康奈尔大学的一名博士后研究员和波士顿学院的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群体的本科生，将参加波士顿学院和康奈尔大学的NSF REU项目。在这个项目中开发的计算工具将被纳入康奈尔纳米科学与技术设施（CNF）的公共计算库。该活动还将通过帮助开发具有理想热传输特性的新材料而造福社会。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。