Photoemission with a twist Attosecond time-resolved spectroscopy provides the ability to probe the fastest electronic processes in atoms and solids. Yet the photoemission process from solids is not fully understood. Siek et al. studied photoemission from the layered van der Waals material WSe2 and found that electron emission occurs as a sequence of events that are apparently time-ordered with respect to rising angular momentum of the involved initial states (see the Perspective by Yakovlev and Karpowicz). This result will help provide a more detailed picture of the photoemission process. Science, this issue p. 1274; see also p. 1239 Attosecond time-resolved spectroscopy reveals angular momentum–induced delays in solid-state photoemission. Attosecond time-resolved photoemission spectroscopy reveals that photoemission from solids is not yet fully understood. The relative emission delays between four photoemission channels measured for the van der Waals crystal tungsten diselenide (WSe2) can only be explained by accounting for both propagation and intra-atomic delays. The intra-atomic delay depends on the angular momentum of the initial localized state and is determined by intra-atomic interactions. For the studied case of WSe2, the photoemission events are time ordered with rising initial-state angular momentum. Including intra-atomic electron-electron interaction and angular momentum of the initial localized state yields excellent agreement between theory and experiment. This has required a revision of existing models for solid-state photoemission, and thus, attosecond time-resolved photoemission from solids provides important benchmarks for improved future photoemission models.

中文翻译：

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通过原子内相互作用增强的固态光电发射中角动量引起的延迟

带有扭曲的光发射阿秒时间分辨光谱提供了探测原子和固体中最快电子过程的能力。然而，固体的光电发射过程尚未完全了解。西克等人。研究了来自分层范德华材料 WSe2 的光发射，发现电子发射作为一系列事件发生，这些事件显然是按照所涉及的初始状态的上升角动量按时间顺序排列的（参见 Yakovlev 和 Karpowicz 的观点）。该结果将有助于提供更详细的光发射过程图片。科学，这个问题 p。1274; 另见第。1239 阿秒时间分辨光谱揭示了角动量引起的固态光电发射延迟。阿秒时间分辨光电子能谱揭示固体的光电子发射尚未完全了解。为范德瓦尔斯晶体二硒化钨 (WSe2) 测量的四个光电发射通道之间的相对发射延迟只能通过考虑传播和原子内延迟来解释。原子内延迟取决于初始局部化状态的角动量，并由原子内相互作用决定。对于 WSe2 的研究情况，光发射事件是按时间顺序排列的，初始状态角动量上升。包括原子内电子-电子相互作用和初始定域状态的角动量，理论和实验之间产生了极好的一致性。这需要修改现有的固态光电发射模型，因此，