近日，美国范德堡大学的Deyu Li及其研究团队取得一项新进展。经过不懈努力，他们发现非平衡声子极化子介导的热传导效应显著。相关研究成果已于2023年10月25日在国际权威学术期刊《自然》上发表。

该研究团队通过系统地测量具有或不具有用于发射SPhPs的金涂层的相同3C-SiC纳米线的热输运，发现热激发SPhPs可以显著提高这些纳米线未涂层部分的导热性。提取的预衰减SPhP热导率比基于平衡玻色-爱因斯坦分布预测的兰道尔极限高出两个数量级以上。研究人员将显著的SPhP电导率归因于非平衡SPhP从金涂层部分有效地发射到未涂层的SiC纳米线中，这一观点得到了SPhP介导的热导率与金涂层长度成正比的观察结果的支持。这些发现为通过引入SPhPs来调制固体中的能量输运提供了新的思路，SPhPs可以有效地抵消许多技术上重要的薄膜中的经典尺寸效应，并改进固态器件的设计。

据悉，表面波能够引发有趣的输运现象。特别是，由红外光和光声子之间的耦合产生的表面声子极化子（SPhPs）已被预测有助于沿极性薄膜和纳米线的热传导。然而，迄今为止的实验结果表明，SPhP对热传导的贡献相当有限。

附：英文原文

Title: Remarkable heat conduction mediated by non-equilibrium phonon polaritons

Author: Pan, Zhiliang, Lu, Guanyu, Li, Xun, McBride, James R., Juneja, Rinkle, Long, Mackey, Lindsay, Lucas, Caldwell, Joshua D., Li, Deyu

Issue&Volume: 2023-10-25

Abstract: Surface waves can lead to intriguing transport phenomena. In particular, surface phonon polaritons (SPhPs), which result from coupling between infrared light and optical phonons, have been predicted to contribute to heat conduction along polar thin films and nanowires. However, experimental efforts so far suggest only very limited SPhP contributions. Through systematic measurements of thermal transport along the same 3C-SiC nanowires with and without a gold coating on the end(s) that serves to launch SPhPs, here we show that thermally excited SPhPs can substantially enhance the thermal conductivity of the uncoated portion of these wires. The extracted pre-decay SPhP thermal conductance is more than two orders of magnitude higher than the Landauer limit predicted on the basis of equilibrium Bose–Einstein distributions. We attribute the notable SPhP conductance to the efficient launching of non-equilibrium SPhPs from the gold-coated portion into the uncoated SiC nanowires, which is strongly supported by the observation that the SPhP-mediated thermal conductivity is proportional to the length of the gold coating(s). The reported discoveries open the door for modulating energy transport in solids by introducing SPhPs, which can effectively counteract the classical size effect in many technologically important films and improve the design of solid-state devices.

DOI: 10.1038/s41586-023-06598-0

Source: https://www.nature.com/articles/s41586-023-06598-0