CDS&E: Coupled Electro-Thermal Transport in Two-Dimensional Materials and Heterostructures

该项目由计算和数据驱动的科学与工程计划资助，由材料研究部门的凝聚态物质和材料理论计划以及化学、生物工程、环境和运输系统部门的热传输过程计划提供资金。非技术总结该奖项支持对模拟工具的开发和应用的计算研究，以模拟二维(2D)材料中的电荷和热载流子的传输。2D材料是一大批新材料，其形式是原子薄片，其厚度只有一个或几个原子。由于它们极薄，这些材料有望成为未来高能效纳米电子和能源设备的平台，这可能使极高密度的集成电路以及可穿戴和多功能电子产品成为可能。材料的电子和热性能不仅相互耦合，而且相互依存：随着温度的升高，电阻急剧增加，这反过来又增加了散热，产生了浪费能源和限制性能的热点。这一点在2D材料中尤为明显，其原子稀薄和与环境的耦合相对较弱，可能会成为热量转移的瓶颈。在这个项目中，PI将开发和发布一个代码，同时处理各种具有科学和技术意义的2D材料中的电荷和热载流子的动力学。将开发的代码将免费分发给社区，并维护一个专门的论坛和文档网站。该奖项还支持PI的教育和推广活动，包括培训和指导下一代计算材料科学家，通过重新设计核心材料课程向各个级别的学生介绍计算科学，招募科学、数学和工程学科中代表性不足的学生，以及创建免费在线教育模块来教授本科生高性能和并行计算。TECHNICAL SUMMARY该奖项支持计算研究，以开发和应用模拟工具来求解二维(2D)材料中电子和声子的耦合玻尔兹曼输运方程。模拟2D纳米结构内的热耗散需要对电子和热进行双向耦合处理，后者通过声子传输。用第一性原理计算电声子耦合，用从头算方法求解电子和声子的玻耳兹曼输运方程，现在已经完全成熟。然而，迫切需要一种能够研究非等温输运的平台，其中同时模拟电子和声子布居，以便跟踪由电子-声子耦合产生的声子，并将其分布/温度反馈到电子输运中，反之亦然。为了满足这一需求，PI将开发并发布一个名为CelhonBTE2D的代码，用于二维材料和异质结构的双向电声耦合玻尔兹曼输运模拟。该代码将建立在第一原理数据的基础上，以实现现实应用的预测性模拟。要开发的代码将通过NanHUB传播，该网站将托管源代码和跟踪使用情况，以及一个专门的论坛和文档网站。该奖项还支持PI的教育和推广活动，包括培训和指导下一代计算材料科学家，通过重新设计核心材料课程，招募STEM学科中代表性不足的学生，以及创建免费在线教育模块向本科生教授高性能和并行计算。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project is funded through the Computational and Data-Enabled Science and Engineering program by contributions from Condensed Matter and Materials Theory program of the Division of Materials Research and the Thermal Transport Processes program of the Division of Chemical, Bioengineering, Environmental, and Transport Systems.NONTECHNICAL SUMMARYThis award supports computational research for the development and applications of a simulation tool to model the transport of charge and heat carriers in two-dimensional (2D) materials. 2D materials are a broad cohort of novel materials in the form of atomically thin sheets having a thickness of only one or a few atoms. Owing to their ultimate thinness, such materials hold tremendous promise as a platform for future energy-efficient nanoelectronic and energy devices, which may enable extremely dense integrated circuits, and wearable and multifunctional electronics. Electronic and thermal properties of materials are not only mutually coupled but strongly interdependent: electrical resistance increases drastically with temperature, which, in turn, increases heat dissipation, creating hot spots that waste energy and limit performance. This is particularly pronounced in 2D materials, whose atomic thinness and relatively weak coupling to the environment may present a bottleneck to heat removal. In this project, the PI will develop and release a code that treats the dynamics of charge and heat carriers concurrently in various 2D materials of scientific and technological relevance. The code to be developed will be disseminated freely to the community, along with maintaining a dedicated website for forums and documentation. This award also supports the PI's educational and outreach activities, which include training and mentoring the next generation of computational materials scientists and introducing computational science to students across levels, by redesigning core materials courses, recruiting underrepresented students in science, math, and engineering disciplines, and creating free online educational modules to teach undergraduate students high-performance and parallel computing.TECHNICAL SUMMARYThis award supports computational research for the development and applications of a simulation tool to solve the coupled Boltzmann transport equations for electrons and phonons in two-dimensional (2D) materials. Simulating thermal dissipation inside 2D nanostructures requires a two-way coupled treatment of electrons and heat, the latter being transported by phonons. Computing electron-phonon coupling from first principles and solving the electron and phonon Boltzmann transport equations using ab initio inputs has now reached full maturity. However, there is a critical need for a platform that will enable studying non-isothermal transport, where electron and phonon populations are simulated concurrently so that phonons generated by electron-phonon coupling are tracked and their distribution/temperature fed back into electron transport and vice versa. To address this need, the PI will develop and release a code, called CelphonBTE2D, for two-way coupled electron-phonon Boltzmann transport simulation of 2D materials and heterostructures. The code will build on first-principles data to enable predictive simulation for realistic applications. The code to be developed will be disseminated via the nanoHUB, which will host source code and track usage, along with a dedicated website for forums and documentation. This award also supports the PI's educational and outreach activities, which include training and mentoring the next generation of computational materials scientists and introducing computational science to students across levels, by redesigning core materials courses, recruiting underrepresented students in STEM disciplines, and creating free online educational modules to teach undergraduate students high-performance and parallel computing.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.