Domain-Engineering Enabled Thermal Switching in Ferroelectric Materials

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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.