We numerically demonstrate that a planar slab made of magnetic Weyl semimetal (a class of topological materials) can emit high-purity circularly polarized (CP) thermal radiation over a broad mid- and long-wave infrared wavelength range for a significant portion of its emission solid angle. This effect fundamentally arises from the strong infrared gyrotropy or nonreciprocity of these materials, which primarily depends on the momentum separation between Weyl nodes in the band structure. We clarify the dependence of this effect on the underlying physical parameters and highlight that the spectral bandwidth of CP thermal emission increases with increasing momentum separation between the Weyl nodes. We also demonstrate, using the recently developed thermal discrete dipole approximation (TDDA) computational method, that finite-size bodies of magnetic Weyl semimetals can emit spectrally broadband CP thermal light, albeit over smaller portion of the emission solid angle compared to the planar slabs. Our work identifies unique fundamental and technological prospects of magnetic Weyl semimetals for engineering thermal radiation and designing efficient CP light sources.

中文翻译：

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来自磁性外尔半金属的宽带圆极化热辐射

我们从数值上证明，由磁性外尔半金属（一类拓扑材料）制成的平板可以在很宽的中波和长波红外波长范围内发射高纯度圆偏振 (CP) 热辐射，其发射的很大一部分立体角。这种效应从根本上源于这些材料的强红外回旋性或非互易性，这主要取决于能带结构中外尔节点之间的动量分离。我们阐明了这种效应对基础物理参数的依赖性，并强调了 CP 热发射的光谱带宽随着外尔节点之间动量分离的增加而增加。我们还证明，使用最近开发的热离散偶极子近似 (TDDA) 计算方法，磁性 Weyl 半金属的有限尺寸体可以发射光谱宽带 CP 热光，尽管与平面板相比，发射立体角的部分更小。我们的工作确定了磁性外尔半金属在工程热辐射和设计高效 CP 光源方面的独特基础和技术前景。