Tavakoli Adib, Maire Jeremie, Brisuda Boris, Crozes Thierry, Motte Jean-François, Saminadayar Laurent, Collin Eddy, Bourgeois Olivier
Univ. Grenoble Alpes, CNRS, Grenoble INP (Institute of Engineering, Univ. Grenoble Alpes), Institut Néel, 38000, Grenoble, France.
Sci Rep. 2022 May 12;12(1):7788. doi: 10.1038/s41598-022-11878-2.
Practical applications of heat transport control with artificial metamaterials will heavily depend on the realization of thermal diodes/rectifiers, in which thermal conductivity depends on the heat flux direction. Whereas various macroscale implementations have been made experimentally, nanoscales realizations remain challenging and efficient rectification still requires a better fundamental understanding of heat carriers' transport and nonlinear mechanisms. Here, we propose an experimental realization of a thermal rectifier based on two leads with asymmetric mass gradients separated by a ballistic spacer, as proposed in a recent numerical investigation, and measure its thermal properties electrically with the microbridge technique. We use a Si[Formula: see text]N[Formula: see text] nanobeam on which an asymmetric mass gradient has been engineered and demonstrate that in its current form, this structure does not allow for thermal rectification. We explain this by a combination of too weak asymmetry and non-linearities. Our experimental observations provide important information towards fabricating rigorous thermal rectifiers in the ballistic phonon transport regime, which are expected to open new possibilities for applications in thermal management and quantum thermal devices.
利用人工超材料控制热传输的实际应用将在很大程度上依赖于热二极管/整流器的实现，其中热导率取决于热流方向。尽管已经通过实验进行了各种宏观尺度的实现，但纳米尺度的实现仍然具有挑战性，并且高效整流仍然需要对热载流子的传输和非线性机制有更好的基本理解。在这里，我们提出了一种基于弹道间隔层分隔的具有不对称质量梯度的两根引线的热整流器的实验实现方案，这是最近一项数值研究中提出的，并使用微桥技术对其热性能进行电学测量。我们使用了一个已设计出不对称质量梯度的Si[公式：见正文]N[公式：见正文]纳米梁，并证明以其当前形式，这种结构不允许热整流。我们将此解释为不对称性和非线性都过于微弱的综合结果。我们的实验观察为在弹道声子输运 regime 中制造严格的热整流器提供了重要信息，预计这将为热管理和量子热器件中的应用开辟新的可能性。
