Extraordinary Polaritonic Heat Conduction

摘要：传热无处不在，在我们的日常生活和工业过程中发挥着重要作用，如计算机芯片的冷却和建筑物的加热。在经典的热物理教科书中，众所周知，固体中传热的主要方式是热传导，众所周知，热传导是缓慢的（以大约音速传播）和扩散的（无方向性）。本项目研究了一种新的热传导机制，将真空中的光和固体中的声结合起来，以高速（光速数量级）和高度定向的方式传导热量。这项研究很重要，因为它可能有助于计算机芯片、发光二极管和建筑物的更有效的热管理等多种应用。通过整合光子学、热科学和纳米技术，该项目提供了一个优秀的跨学科平台来教育和培训物理学和工程学的女研究生，并为来自少数族裔的本科生和当地高中生提供有吸引力的动手实验经验。技术摘要：固体中的热传导通常被描述为与声子和电子等主要热载体相关的短平均自由程（MFP为10微米）扩散过程。本项目的目的是在理论和实验上研究由表面声子极化子（SPhP）介导的热传导新体制下的异常热输运现象，SPhP起源于光学声子和光子之间的耦合。SPhP沿极性介电材料及其周围环境之间的界面高度受限，因此可以携带高能量通量，与固体中的声子相当甚至更高。在适当的条件下，即使在室温和高温下，SPhP也可以具有极长的传播长度（mm或更长），因此可以在更长的距离内表现出非凡的行为。本项目利用纳米级器件制造和高分辨率纳米瓦量热法的新颖实验技术，结合严格的理论建模和数值模拟，探索极性介电纳米结构中特殊的SPhP热传导现象，包括低维热传导、非扩散和量子热输运以及动态可调热输运。该材料研究部（DMR）拨款支持研究由表面声子极化子介导的热传导新制度下的特殊热传输现象，该研究由数学和物理科学理事会DMR的凝聚态物理（CMP）计划资助。该奖项反映了美国国家科学基金会的法定使命，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 Abstract: Heat transfer is ubiquitous and plays an important role in our daily lives and industrial processes, such as cooling of computer chips and heating of buildings. In classical textbooks of thermal physics, it is well known that the dominant mode of heat transfer in solids is heat conduction, which is known to be slow (travels at around the speed of sound) and diffusive (non-directional). This project studies a new heat conduction mechanism that combines the light in vacuum and sound in solids to conduct heat at high speed (on the order of speed of light) and with a high degree of directionality. The study is important as it may contribute to diverse applications such as more efficient thermal management of computer chips, light emitting diodes, and buildings. By integrating photonics, thermal science, and nanotechnologies, the project provides an excellent interdisciplinary platform to educate and train female graduate students in physics and engineering and offers attractive hands-on laboratory experience for undergraduate and local high-school students from underrepresented minority groups. Technical Abstract: Heat conduction in solids is normally described as a diffusion process with short mean free path (MFP 10 microns) associated with the main heat carriers, such as phonons and electrons. The goal of this project is to theoretically and experimentally investigate extraordinary thermal transport phenomena in a new regime of heat conduction mediated by surface phonon polariton (SPhP), which originates from the coupling between optical phonon and photon. SPhP is highly confined along the interface between a polar dielectric material and its surroundings and thus can carry high energy flux, comparable to or even higher than that of phonons in a solid. Under suitable conditions, SPhP can have extremely long propagation lengths (mm or longer) even at room and high temperature, and therefore, can exhibit extraordinary behaviors over a much longer distance. The project utilizes novel experimental techniques in nanoscale device fabrication and high-resolution nano-watt calorimetry, combined with rigorous theoretical modeling and numeric simulation, to explore extraordinary SPhP heat conduction phenomena in polar dielectric nanostructures, including low-dimensional heat conduction, non-diffusive and quantum thermal transport, and dynamically tunable thermal transport.This Division of Materials Research (DMR) grant supports research to investigate extraordinary thermal transport phenomena in a new regime of heat conduction mediated by surface phonon polariton with funding from the Condensed Matter Physics (CMP) Program in the DMR of the Mathematical and Physical Sciences Directorate.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.