Near-field radiative transfer by bulk hyperbolic polaritons across vacuum gap
Near-field radiative transfer by bulk hyperbolic polaritons across vacuum gap
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DOI：
10.1016/j.ijheatmasstransfer.2021.120984
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发表时间：
2021-05
影响因子：
5.2
通讯作者：
H. Salihoglu;Xianfan Xu
中科院分区：
文献类型：
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作者：
H. Salihoglu;Xianfan Xu
热辐射一直被视为一种表面现象。最近的一项研究表明，新的辐射通道，即双曲声子极化子，可以在热流密度相当于传导的情况下促进块状双曲材料内部的热传递。对于双曲材料之间真空缝隙的近场辐射传输，双曲声子极化子被认为是负责强化换热的表面模。在这里，我们分析了由块体材料内部温度梯度驱动的双曲声子极化子的近场辐射传输。我们发展了一个介观尺度的多体散射方法来解释双曲声子极化子在体内和真空缝隙中的辐射传输中的作用。我们的研究指出了在材料中没有温度梯度的情况下，体生成模和表面模之间的等价性，从而为双曲声子极化子近场辐射传输提供了统一的框架。结果还阐明了体生模式和体温分布在增强近场辐射传输中的贡献。
Thermal radiation has always been treated as a surface phenomenon. A recent study has demonstrated that new radiation channels, the hyperbolic phonon polaritons, can contribute to heat transfer inside bulk hyperbolic materials with a heat flux comparable to conduction. For near-field radiative transfer across a vacuum gap between two hyperbolic materials, hyperbolic phonon polaritons have been considered as surface modes that are responsible for heat transfer enhancement. Here, we analyze near-field radiative transfer due to hyperbolic phonon polaritons, driven by temperature gradient inside the bulk materials. We develop a mesoscale many-body scattering approach to account for the role of hyperbolic phonon polaritons in radiative transfer in the bulk and across a vacuum gap. Our study points out the equivalency between the bulk-generated mode and the surface mode in the absence of a temperature gradient in the material, and hence provide a unified framework for near-field radiative transfer by hyperbolic phonon polaritons. The results also elucidate contributions of the bulk-generated mode and the bulk temperature profile in the enhanced near-field radiative transfer.