物理学教室 談話会(3月10日)

コロキウム・談話会 2025/02/27

演目:Graphite thermal Tesla valve
講師:野村 政宏 教授
所属:東京大学 生産技術研究所
日時:2025年3月10日(月)10時~11時30分
場所:理学部4号館3階 1320室(Zoom ハイブリッド開催)

※ 言語は日本語、スライドは英語でご講演下さる予定です。
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https://u-tokyo-ac-jp.zoom.us/meeting/register/X8giz_03Rl68nHMWRIzpCQ

 

As electronic devices become increasingly compact and powerful, efficient thermal
management is crucial for performance, reliability, and safety. This study explores a novel
approach to thermal rectification by extending the concept of the Tesla valve, originally
designed for fluid flow, to solid-state heat conduction in graphite materials.
We utilized isotopically enriched graphite with 13C content reduced from 1.1% to 0.02% to
create a solid-state Tesla valve structure. This material exhibits phonon hydrodynamic behavior,
allowing for the formation of phonon Poiseuille flow [1]. We observed thermal rectification
effects of up to 15% in the temperature range of 25-60 K. The graphite Tesla valve was
fabricated as an air-bridge structure with a thickness of 90 nm and a width of 4.5 μm to ensure
heat flow exclusively within the graphite. Thermal conductivity measurements were performed
on forward and reverse configurations at various temperatures.
Our results demonstrate that the thermal rectification effect is most pronounced at around 45
K, where the thermal conductivity in the forward direction is 15.4% higher than in the reverse
direction. This effect was observed only within the temperature range where phonons exhibit
fluid-like properties [2]. This research represents a significant step towards realizing solid-state
thermal rectification devices by leveraging the hydrodynamic behavior of phonons in graphite.
Developing such thermal management technologies could lead to substantial advancements in
the performance and efficiency of various electronic devices.

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Fig. 1. (a) Illustration of the liquid flow in a Tesla valve structure. (b) Optical microscope image of the
fabricated graphite Tesla valve structures. (c) Observed thermal rectification in the hydrodynamic regime.
[1] X. Huang, et al., “Observation of phonon Poiseuille flow in isotopically purified graphite ribbons”, Nat.
Commun. 14, 2044 (2023).
[2] X. Huang, et al., “A graphite thermal Tesla valve driven by hydrodynamic phonon transport,” Nature 634,1086-1090 (2024); プレスリリース「テスラバルブの概念を固体熱伝導に拡張し、熱整流に成功――フォノンの流体的性質を用いた新しい熱機能デバイスに期待――」 https://www.iis.u-tokyo.ac.jp/ja/news/4619/

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