講演情報
[17a-K205-3]Observation and application of hydrodynamic heat transport in microscale graphite
〇Xin Huang1, Masahiro Nomura1 (1.IIS, Univ. of Tokyo)
キーワード：
Hydrodynamic heat transport、Phonon Poiseuille flow、Thermal rectification
Hydrodynamic heat transport has been intensively reviewed owing to its peculiar phonon collective behaviours, which are very similar to fluid dynamics. However, observation of phonon Poiseuille flow in graphite is rarely claimed due to the experimental difficulties and missing theoretical understanding, not to mention its practical applications in the design of new semiconductor devices.
Here, we first experimentally investigate hydrodynamic heat transport in microscale graphite ribbons with purified (0.02% 13C) carbon isotope concentrations. We advocate more straightforward and rigorous criteria for ascertaining hydrodynamic phonon flow - a faster rise of κ than the ballistic thermal conductance (Gballistic). The value of κ/Gballistic is enhanced by 51% from 40 to 90 K, this super-ballistic scaling of thermal conductivity with temperature is unambiguous evidence of hydrodynamic phonon Poiseuille flow.
Next, based on our novel understanding of the occurrence criteria of phonon Poiseuille flow, we extend our investigation to its application of thermal rectification inspired by the Tesla valve (TV) of fluid flows. We fabricate asymmetric TV structures in a 90 nm thick purified graphite sample. In the forward direction, hydrodynamic phonons predominantly traverse from the heat source to the sink via the main channel. Conversely, in the reverse case, two distinct hydrodynamic phonon flows diverge from the heat source. The convergence of these two flows leads to a loss of phonon momentum and introduces resistance to thermal transport. This phenomenon results in a notable disparity between κf and κb in the temperature range of 20 to 60 K. This investigation elucidates thermal rectification in solid graphite TVs, thereby paving the way for novel approaches in thermal management leveraging phonon hydrodynamics.
Here, we first experimentally investigate hydrodynamic heat transport in microscale graphite ribbons with purified (0.02% 13C) carbon isotope concentrations. We advocate more straightforward and rigorous criteria for ascertaining hydrodynamic phonon flow - a faster rise of κ than the ballistic thermal conductance (Gballistic). The value of κ/Gballistic is enhanced by 51% from 40 to 90 K, this super-ballistic scaling of thermal conductivity with temperature is unambiguous evidence of hydrodynamic phonon Poiseuille flow.
Next, based on our novel understanding of the occurrence criteria of phonon Poiseuille flow, we extend our investigation to its application of thermal rectification inspired by the Tesla valve (TV) of fluid flows. We fabricate asymmetric TV structures in a 90 nm thick purified graphite sample. In the forward direction, hydrodynamic phonons predominantly traverse from the heat source to the sink via the main channel. Conversely, in the reverse case, two distinct hydrodynamic phonon flows diverge from the heat source. The convergence of these two flows leads to a loss of phonon momentum and introduces resistance to thermal transport. This phenomenon results in a notable disparity between κf and κb in the temperature range of 20 to 60 K. This investigation elucidates thermal rectification in solid graphite TVs, thereby paving the way for novel approaches in thermal management leveraging phonon hydrodynamics.