Control of thermal transport at the nanoscale is of great current interest for creating novel thermal logic and energy conversion devices. Recent experimental studies have demonstrated that radiative heat transfer between macroscopic objects separated by nanogaps, or between nanostructures located in the far-field of each other, can exceed the blackbody limit. Here, we present a novel scheme to actively control the radiative heat current between individual nanostructures separated by far-field distances (i.e. gap separation larger than the peak thermal wavelength, \~10 µm at room temperature). Specifically, we demonstrate that the radiative heat current between two coplanar nanomembranes comprised of silicon nitride (SiN) can be modulated by factors as large as five by bringing a third planar object into close proximity of the membranes. This switching scheme was demonstrated using high-resolution calorimetry and a custom-built nanopositioner. Numerical modelling reveals that this modulation is due to a modification of guided modes supported in the SiN nanomembranes via evanescent interactions with the third object. This multi-body effect, which is not significant for macroscopic objects in the far-field, could offer an efficient pathway for active control of heat flow at the nanoscale, eventually leading to the development of practical switches of radiative heat currents, as well as tunable filters that can effectively modify the heat transfer spectrum for a particular application.


Nanoscale Radiative Thermal Switching via Multi-Body Effects

Division / Sponsors: 
Heat Transfer Division (HTD), Fluids Engineering Division (FED)

Heat Transfer Summer Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/HT/HT2020/volume/83709

18th International Conference on Nanochannels, Microchannels, and Minichannels
Paper Proceedings: https://asmedigitalcollection.asme.org/ICNMM/ICNMM2020/volume/83693

Fluids Engineering Division Summer Meeting
Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2020/volume/83716

HT-ICNMM2020 - Virtual Conference, SHTC - Virtual Conference, FEDSM2020 - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.