Session: 11-58-01: Nanoscale Thermal Transport

Paper Number: 120068

120068 - Phonon Scattering Engineered Thermal Radiative Transport at Nanoscales 

Nonlinear heat transfer, in contrast to conventional heat transfer, describes a phenomenon where the heat flux does not exhibit a linear dependence on the temperature difference between two reservoirs. It serves as the underlying mechanism for various nonlinear thermal circuit components, including thermal switches, thermal diodes, thermal regulators, and negative differential thermal conductance (NDTC) devices. Similar to their electronic counterparts, nonlinear thermal circuits play a significant role in controlling the thermal transport in diverse applications such as renewable energy conversion and harvesting, thermal energy storage, personal and building thermal comfort, spacecraft thermal management, and cooling of electronic devices and data centers. Developing high-performance nonlinear thermal components holds significant potential in tackling global challenges such as the climate crisis, energy shortages, carbon emissions, and environmental pollution.

While nonlinear heat transfer is a natural occurrence in the boiling and convection process, research investigations into these solid-state nonlinear thermal devices through conduction and radiation only began this century. NDTC refers to a nonlinear thermal transport phenomenon where heat flow decreases as the temperature difference increases, i.e. dQ/dT < 0. Thermal regulator and thermal diode are fundamental components of nonlinear thermal circuits, and they can be realized using either conduction or radiation to control thermal transport while maintaining the solid-state condition. Compared to conduction-based nonlinear thermal devices, radiative thermal regulators and diodes tend to offer better performance due to the inherent nonlinearity of radiative heat transfer. However, in order to achieve optimal performance in nonlinear radiative thermal devices, previous research has predominantly utilized intricate surface or layered nanostructures, as well as phase change materials (PCMs). These approaches have limitations such as the fabrication complexity of nanostructures and the fixed working temperature determined by the critical temperature of PCMs.

While isotope enrichment techniques have unlocked the potential of phonon linewidth engineering in nonlinear heat transfer, its practical applications remain limited. In this work, we investigate the potential of isotope engineering to control near-field radiative heat transfer between two Boron Arsenide (BAs) bulks. Our study theoretically demonstrates the realization of a tunable radiative heat flux regulator with infinite switching ratio by leveraging the temperature-dependent phonon linewidth combined with near-field radiation. Furthermore, we achieve a range of nonlinear radiative transfer devices, including NDTC devices and temperature thermal regulators. By adjusting the isotope concentrations, we can tune the operating temperature of the NDTC device and the stable temperature range of the thermal regulators. Additionally, by introducing asymmetry in the isotope composition of one of the terminals, we create a radiative thermal diode. These results emphasize the effectiveness of isotope engineering in achieving adjustable performance characteristics in nonlinear radiative thermal devices. Furthermore, this integration of phonon and photon science in controlling heat flux at the nanoscale holds significant promise for advancing thermal management and modulation applications.

Presenting Author: Dudong Feng Purdue University

Presenting Author Biography: Dr. Dudong Feng is a postdoctoral research fellow at the school of mechanical engineering at Purdue University. He completed his Ph.D. degree in mechanical engineering from Georgia Institute of Technology. His current research interests include near-field radiation with applications on radiative energy converters and thermal management, first-principles calculation for materials screening, thermophotonics and polaritonics.

Authors:

Dudong Feng Purdue University
Xiulin Ruan Purdue University