Domain-Engineering Enabled Thermal Switching in Ferroelectric Materials

非技术描述：如今，尽管能源和电子行业对能量调节有着强烈的需求，但实现对固态材料热导率的主动和可逆控制的手段非常有限。一个有前途的策略是操纵可重构界面的材料与大量的热阻热流。该项目推进了当前对这些可重构接口之间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的广泛应用具有转化意义，例如废热能量转换，能量收集和集成电子设备的固态冷却。研究和教育是通过激励和培养学生追求科学和工程职业的重点相结合，特别是在可持续能源和先进电子领域的材料。技术难题：关于热能如何在铁电材料中可重构畴壁中转移的基本机制知之甚少。因此，该项目的重点是阐明铁电畴壁的作用，特别是它们的空间分布（例如，密度、取向和形状各向异性）对Kapitza电阻和热传输的影响。采用互补的理论和实验方法：（1）测量铁电薄膜和单晶的各向异性热导率以揭示畴壁处的Kapitza电阻对畴结构和温度的依赖性;（2）进行分子动力学模拟以分析Kapitza电阻如何依赖于能量载流子的相互作用（即，声子）与畴壁。这些研究活动的目的是推进目前的理解微观热输运机制的铁电材料。外联活动正在开发电影360虚拟现实实验室图尔斯之旅，以“传送”在线K-12学生进入实验室，以可视化材料研究和可持续能源应用。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节能，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知识价值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.