论文标题
在时间和角度分辨的光发射光谱中，使用圆形二分性能在WSE $ _2 $中探测拓扑浮雕状态
Probing Topological Floquet States in WSe$_2$ using Circular Dichroism in Time- and Angle-Resolved Photoemission Spectroscopy
论文作者
论文摘要
观察材料中光引起的浮雕拓扑状态的特征已被证明非常具有挑战性。角度分辨光发射光谱（ARPE）非常适合研究浮子物理学，因为它允许直接探测驱动固体的着装电子状态。根据系统的不同，散射和破坏性可以发挥重要作用，从而阻碍了浮子状态的出现。另一个挑战是将Floquet侧带从激光辅助光发射（LAPE）中解散，因为这两种都导致ARPES Spectra中的类似签名。在这里，我们调查了浮球状态在过渡金属二进制中的出现$ 2H $ -WSE $ _2 $，这是观察Floquet Physics的最有前途的系统之一。我们讨论了浮光拓扑状态如何在光电子角分布（CDAD）中的圆形二色性特征中表现出来，这些特征是由瞬态带结构修饰和轨道角动量的相关纹理确定的。将光发射矩阵元素的高度精确建模与\ emph {ab intio}的描述相互作用，我们研究了可以在当前最新的实验设置中实现的模式。预测的特征对散射效应具有鲁棒性，预计将在即将进行的实验中观察到。
Observing signatures of light-induced Floquet topological states in materials has been shown to be very challenging. Angle-resolved photoemission spectroscopy (ARPES) is well suited for the investigation of Floquet physics, as it allows to directly probe the dressed electronic states of driven solids. Depending on the system, scattering and decoherence can play an important role, hampering the emergence of Floquet states. Another challenge is to disentangle Floquet side bands from laser-assisted photoemission (LAPE), since both lead to similar signatures in ARPES spectra. Here, we investigate the emergence of Floquet state in the transition metal dichalcogenide $2H$-WSe$_2$, one of the most promising systems for observing Floquet physics. We discuss how the Floquet topological state manifests in characteristic features in the circular dichroism in photoelectron angular distributions (CDAD) that is determined by the transient band structure modifications and the associated texture of the orbital angular momentum. Combining highly accurate modeling of the photoemission matrix elements with an \emph{ab initio} description of the light-matter interaction, we investigate regimes which can be realized in current state-of-the-art experimental setups. The predicted features are robust against scattering effects and are expected to be observed in forthcoming experiments.
