Huang Xin, Masubuchi Satoru, Watanabe Kenji, Taniguchi Takashi, Machida Tomoki, Nomura Masahiro
Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan.
Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
Nanomaterials (Basel). 2023 Jun 13;13(12):1854. doi: 10.3390/nano13121854.
The super-ballistic temperature dependence of thermal conductivity, facilitated by collective phonons, has been widely studied. It has been claimed to be unambiguous evidence for hydrodynamic phonon transport in solids. Alternatively, hydrodynamic thermal conduction is predicted to be as strongly dependent on the width of the structure as is fluid flow, while its direct demonstration remains an unexplored challenge. In this work, we experimentally measured thermal conductivity in several graphite ribbon structures with different widths, from 300 nm to 1.2 µm, and studied its width dependence in a wide temperature range of 10-300 K. We observed enhanced width dependence of the thermal conductivity in the hydrodynamic window of 75 K compared to that in the ballistic limit, which provides indispensable evidence for phonon hydrodynamic transport from the perspective of peculiar width dependence. This will help to find the missing piece to complete the puzzle of phonon hydrodynamics, and guide future attempts at efficient heat dissipation in advanced electronic devices.
由集体声子促成的热导率的超弹道温度依赖性已得到广泛研究。它被认为是固体中流体动力学声子输运的确凿证据。另外，预计流体动力学热传导与流体流动一样强烈依赖于结构的宽度，而其直接证明仍是一个未被探索的挑战。在这项工作中，我们通过实验测量了几种宽度从300纳米到1.2微米不等的石墨带结构的热导率，并在10 - 300 K的宽温度范围内研究了其对宽度的依赖性。我们观察到，与弹道极限相比，在75 K的流体动力学窗口内热导率对宽度的依赖性增强，这从独特的宽度依赖性角度为声子流体动力学输运提供了不可或缺的证据。这将有助于找到完成声子流体动力学难题的缺失部分，并指导未来在先进电子设备中进行高效散热的尝试。
