论文标题
光轴电动力学的理论和在拓扑抗铁磁铁中的KERR效应的应用理论
Theory of optical axion electrodynamics and application to the Kerr effect in topological antiferromagnets
论文作者
论文摘要
磁电介质中的新兴轴突电动力学有望提供新颖的方法来检测和控制电磁场的材料特性。但是，尽管经过了十多年的深入研究，但其理论理解仍然局限于静态极限。在这里，我们在一般频率下介绍了轴突电动力学理论。我们通过与光学表面霍尔电导率的关系定义了适当的光轴磁电耦合，并提供了在晶格系统中计算它的方法。通过采用我们的公式，我们表明轴支电动力学可以在薄膜抗iferromagnets中产生显着的kerr效应，而波长似乎太长了，无法解决磁性的空间调节。我们确定了抑制KERR效应的波长量表。我们的理论与Mnbi $ _2 $ TE $ _4 $之类的材料特别相关，$ _4 $，这是一种拓扑抗fiferromagnet，其磁电响应在此显示，即使在光频率下，此处也以轴贡的贡献为主。
Emergent axion electrodynamics in magneto-electric media is expected to provide novel ways to detect and control material properties with electromagnetic fields. However, despite being studied intensively for over a decade, its theoretical understanding remains mostly confined to the static limit. Here, we introduce a theory of axion electrodynamics at general frequencies. We define a proper optical axion magneto-electric coupling through its relation to optical surface Hall conductivity and provide ways to calculate it in lattice systems. By employing our formulas, we show that axion electrodynamics can lead to a significant Kerr effect in thin-film antiferromagnets at wavelengths that are seemingly too long to resolve the spatial modulation of magnetism. We identify the wavelength scale above which the Kerr effect is suppressed. Our theory is particularly relevant to materials like MnBi$_2$Te$_4$, a topological antiferromagnet whose magneto-electric response is shown here to be dominated by the axion contribution even at optical frequencies.
