ABSTRACT

We propose a thermal modulation structure made of two identical SiO₂ slabs coated by Dirac semimetal (DSM) films and separated by a nanoscale vacuum gap. The energy transmission probability reveals that the coupled surface plasmon polaritons (SPPs) between the two DSM films, and the surface phonon polaritons (SPhPs) supported by the SiO₂ substrate can vary sensitively with the Fermi level, the degenerate factor of 3D Dirac points and the thickness of the DSM film, thus providing the possibilities for modulating the radiative heat transfer by tuning these parameters. Based on Maxwell’s equations incorporating fluctuational electrodynamics, the effects of these parameters on the heat transfer coefficient and the thermal modulation contrast are numerically analyzed. Under proper parameters, higher modulation contrasts are obtained by continuously tuning the Fermi level from 0.05 eV to 0.3 eV. The obtained results might be helpful in designing a DSM-based thermal modulator with higher modulation contrasts.

摘要

我们提出了一种热调制结构，由两个相同的 SiO ₂板制成，由狄拉克半金属 (DSM) 薄膜涂覆并由纳米级真空间隙隔开。能量传输概率表明，两个 DSM 薄膜之间的耦合表面等离子体激元 (SPPs) 以及由 SiO ₂支撑的表面声子激元 (SPhPs)衬底可以随着费米能级、3D Dirac 点的简并因子和 DSM 薄膜的厚度而敏感地变化，从而提供了通过调整这些参数来调节辐射传热的可能性。基于结合波动电动力学的麦克斯韦方程组，数值分析了这些参数对传热系数和热调制对比度的影响。在适当的参数下，通过将费米能级从 0.05 eV 连续调谐到 0.3 eV，可以获得更高的调制对比度。获得的结果可能有助于设计具有更高调制对比度的基于 DSM 的热调制器。