Broadband and Wide Angle Nonreciprocal Thermal Emission from Weyl Semimetal Structures
Broadband and Wide Angle Nonreciprocal Thermal Emission from Weyl Semimetal Structures
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DOI：
10.1364/josab.495725
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发表时间：
2023-06
期刊：
影响因子：
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通讯作者：
A. Butler;C. Argyropoulos
中科院分区：
文献类型：
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作者：
A. Butler;C. Argyropoulos
非互反热辐射是一项前沿技术，可以实现对热辐射的基本控制，在热能收集方面具有令人兴奋的应用。然而，到目前为止，最大的挑战之一是使非互反发射在宽波长范围和多角度下工作。在这项工作中，我们通过提出三种不同类型的结构来解决这个突出的问题，这些结构总是只使用一个Weyl半金属（WSM）薄膜，结合一个或两个额外的介电或金属层，并以金属衬底终止。首先，建立了基于WSM薄膜厚度的热非互易对比度大小和带宽之间的权衡关系。然后，通过插入介电间隔层来证明带宽增宽效应，该间隔层也可以通过改变其厚度来微调。最后，通过在提出的少层设计中添加薄金属层来进一步控制所产生的强非互易热辐射。所提出的复合材料结构具有宽频率范围和多发射角，对各种非互易热辐射应用具有非常有利的性能。此外，所提出的设计不需要任何图案化，可以通过简单的沉积制造方法实验实现。它们有望帮助创造宽带非互易热辐射体，可以在新的能量收集设备中找到应用。
Nonreciprocal thermal emission is a cutting-edge technology that enables fundamental control over thermal radiation and has exciting applications in thermal energy harvesting. However, so far one of the foremost challenges is making nonreciprocal emission to operate over a broad wavelength range and for multiple angles. In this work, we solve this outstanding problem by proposing three different types of structures always utilizing only one Weyl semimetal (WSM) thin film combined with one or two additional dielectric or metallic layers and terminated by a metallic substrate. First a tradeoff relationship between the magnitude and bandwidth of the thermal nonreciprocity contrast is established based on the thickness of the WSM film. Then, the bandwidth broadening effect is demonstrated via the insertion of a dielectric spacer layer that can also be fine-tuned by varying its thickness. Finally, further control on the resulting strong nonreciprocal thermal radiation is demonstrated by the addition of a thin metallic layer in the proposed few layer designs. The presented composite structures work for a broad frequency range and multiple emission angles, consisting highly advantageous properties to various nonreciprocal thermal radiation applications. Moreover, the proposed designs do not require any patterning and can be experimentally realized by simple deposition fabrication methods. They are expected to aid in the creation of broadband nonreciprocal thermal emitters that can find applications in new energy harvesting devices.