CAREER: Prediction and understanding of thermal transport across successive interfaces

许多尖端应用需要在连续的材料层上进行热流管理。例如，在雷达、5G站、卫星通信、适配器、逆变器和充电器中使用的电力电子和射频电子设备中，模块中产生的大量热量需要通过晶体管中的多层半导体快速消散。在热障涂层、高超声速飞行器热防护和热电器件中，大量的热量需要由几层不同的材料阻挡。然而，通过连续层和界面的热传输尚未得到很好的理解，阻碍了下一代芯片，电子，发动机，高超音速飞行器和其他应用的合理设计。因此，该项目的主要目的是提供准确的预测和深入了解不同材料的连续层和界面的热传输。该项目还将包括重要的教育活动，包括为当地社区的K-12学生提供实践科学工具包和讲座，为孩子们提供在线视频，为高中生提供研究实习机会，以及免费的在线研究生课程。该项目的目标是建立对两个或多个连续固体界面之间声子热输运的全面理解，建立一个形式主义和连续界面热输运的模拟框架，准确预测几个技术上重要的宽带隙半导体异质结构的热输运，并使用不同的方法提高从幼儿园到研究生水平的现代科学和工程教育。该项目将（1）建立高精度的机器学习基于原子间势的分子动力学模拟，用于连续界面热输运预测;（2）开发能够进行双重和多重界面热输运的新Landauer形式;（3）开发新的声子Boltzmann输运框架，用于连续界面热输运;以及（4）揭示了界面热导率、热导率、模式分辨声子透射、反射、温度和热通量如何受到（i）第二界面的存在和距离，（ii）界面的粗糙度，（iii）包括界面的材料，（iv）外部热源中的声子激发，（v）远离界面的条件，例如膜内部的杂质和边缘的粗糙度，以及（vi）更多界面的存在。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Many cutting-edge applications require heat flow management across successive layers of materials. For example, in the power electronics and radiofrequency electronics used in radars, 5G stations, satellite communications, adapters, inverters, and chargers, the extensive heat generated in the modules needs to be dissipated rapidly through multiple layers of semiconductors in the transistors. In the thermal barrier coatings, hypersonic aircraft thermal protection, and thermoelectrics, the extensive heat needs to be blocked by several layers of different materials. However, heat transport through successive layers and interfaces has not been well understood, impeding the rational design of next-generation chips, electronics, engines, hypersonic vehicles, and other applications. Therefore, the principal aim of this project is to provide an accurate prediction and a deep understanding of thermal transport across successive layers and interfaces of different materials. The project will also encompass significant educational activities, including hands-on science kits and lectures for K-12 students in various local communities, online videos for kids, research internship opportunities for high school students, and a free online graduate course.The goal of this project is to establish a comprehensive understanding of phonon thermal transport across two or more successive solid interfaces, build a formalism and a simulation framework for successive interfacial thermal transport, accurately predict the thermal transport across several technologically important wide-bandgap semiconductor heterostructures, and enhance modern science and engineering education from kindergarten to graduate levels using diverse methods. The project will (1) establish high-accuracy machine learning interatomic potential-based molecular dynamics simulations for successive interfacial thermal transport predictions; (2) develop new Landauer’s formalisms capable of double and multiple interfacial thermal transport; (3) develop a new phonon Boltzmann transport framework for successive interfacial thermal transport; and (4) reveal how the interfacial thermal conductance, thermal conductivity, mode-resolved phonon transmission, reflection, temperature, and heat flux are affected by (i) the presence of and distance from a second interface, (ii) the roughness of the interfaces, (iii) the materials comprising the interfaces, (iv) the phonon excitations in the external heat source, (v) the conditions far from the interface such as the impurities inside the film and the roughness of edges, and (vi) the presence of more interfaces. The results will be integrated into educational programs to enhance learning from kindergarten to graduate levels.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.