Domain-Engineering Enabled Thermal Switching in Ferroelectric Materials

非技术描述：今天，尽管能源和电子行业对能源监管有强烈的需求，但实现对固态材料导热系数的主动和可逆控制的手段极其有限。一种有希望的策略是操纵材料中的可重新配置的界面，这些材料对热流具有显著的热阻。该项目促进了当前对这些可重构界面上的热传输机制的基本理解。这项研究对可持续能源基础设施中的广泛应用具有翻译意义，如余热转换、能量收集和集成电子产品的固态冷却。研究和教育是通过重点激励和培训学生追求科学和工程职业，特别是在可持续能源和先进电子材料领域的研究和教育相结合的。技术细节：铁电材料中热能如何通过可重新配置的磁区壁传递的基本机制鲜为人知。因此，本项目的重点是阐明铁电畴壁对Kapitza电阻和热输运的作用，特别是它们的空间分布(如密度、取向和形状各向异性)。采用理论和实验相结合的方法：(1)测量了铁电薄膜和单晶的各向异性热导率，揭示了磁畴壁的Kapitza电阻与磁畴结构和温度的依赖关系；(2)采用分子动力学模拟的方法，分析了Kapitza电阻与载流子(即声子)与磁畴壁的相互作用。这些研究活动旨在促进当前对铁电材料微观热输运机制的理解。外展活动正在开发电影般的360虚拟现实实验室之旅，将K-12学生‘传送’到实验室，使材料研究和在可持续能源中的应用可视化。本科生和研究生通过跨学科的研究经验进行培训，以促进可持续能源基础设施中能源节约、热管理和能源转换的重要性和挑战。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。

NON-TECHNICAL DESCRIPTION: Today, the means to realize active and reversible control over thermal conductivity in solid-state materials are extremely limited, despite the strong demands from both the energy and electronics industries for energy regulation. One promising strategy is to manipulate reconfigurable interfaces in materials with substantial thermal resistances to heat flow. This project advances the current fundamental understanding on the thermal transport mechanisms across these reconfigurable interfaces. This research has translational implications for a wide range of applications in the sustainable energy infrastructure, such as waste-heat energy conversion, energy harvesting, and solid-state cooling for integrated electronics. Research and education are integrated through a focus on motivating and training students to pursue science and engineering occupations, specifically in the areas of materials for sustainable energy and advanced electronics.TECHNICAL DETAILS: Fundamental mechanisms on how the thermal energy is transferred across reconfigurable domain walls in ferroelectric materials is poorly understood. Therefore, the focus of the project is to elucidate the roles of ferroelectric domain walls, especially their spatial distribution (e.g., density, orientation, and shape anisotropy), on the Kapitza resistance and thermal transport. Complementary theoretical and experimental approaches are applied: (1) The anisotropic thermal conductivity of ferroelectric thin films and single crystals are measured to reveal the dependence of Kapitza resistance at domain walls on the domain structures and temperature; (2) Molecular dynamics simulation is conducted to analyze how the Kapitza resistance depends on the interactions of energy carriers (i.e., phonons) with domain walls. These research activities aim to advance the current understanding on the microscopic thermal transport mechanisms in ferroelectric materials. The outreach activities are developing cinematic 360 virtual-reality laboratory tours to ‘teleport’ on-line K-12 students into the laboratory to visualize materials research and applications in sustainable energy. Undergraduate and graduate students are trained through interdisciplinary research experiences to promote the importance and challenges of energy savings, thermal management, and energy conversion in sustainable energy infrastructure.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.