The properties of kagome metals are governed by the interdependence of band topology and electronic correlations resulting in remarkably rich phase diagrams. Here, we study the temperature evolution of the bulk electronic structure of the antiferromagnetic kagome metal FeGe using infrared spectroscopy. We uncover drastic changes in the low-energy interband absorption at the 100 K structural phase transition that has been linked to a charge-density-wave (CDW) instability. We explain this effect by the minuscule Fe displacement in the kagome plane, which results in parallel bands in the vicinity of the Fermi level. In contrast to conventional CDW materials, however, the spectral weight shifts to low energies, ruling out the opening of a CDW gap in FeGe.

中文翻译：

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反铁磁性 Kagome 金属 FeGe 中有趣的低温相


Kagome 金属的性质受能带拓扑和电子相关性的相互依赖性控制，从而产生非常丰富的相图。在这里，我们使用红外光谱研究了反铁磁 kagome 金属 FeGe 的体电子结构的温度演化。我们发现 100 K 结构相变时低能带间吸收的巨大变化与电荷密度波 (CDW) 不稳定性有关。我们通过戈薇平面中微小的 Fe 位移来解释这种效应，这导致费米能级附近出现平行能带。然而，与传统的 CDW 材料相比，光谱权重转向低能量，排除了 FeGe 中 CDW 间隙的打开。