石墨烯中具有持久赝自旋极化的光激发非热电子动量空间观测
Momentum-space Observation of Optically Excited Non-Thermal Electrons in Graphene with Persistent Pseudospin Polarization
AI总结：
本文利用时间分辨动量显微技术观测石墨烯中光激发非热电子的动量分布与赝自旋极化，并通过调节激发通量揭示电子-电子散射对极化弛豫的影响，为二维材料研究和石墨烯器件设计提供依据。
摘要：
石墨烯独特的光学性质，包括宽带吸收和超快响应，使其成为光电子和自旋电子器件中的关键组成部分。利用具有高数据率和高动态范围的时间分辨动量显微技术，我们报道了可见光激发到石墨烯导带的电子及其后续弛豫过程的动量空间测量。我们观察到新生的光激发电子具有明显的非热分布，并带有晶格赝自旋极化，与简单紧束缚理论的结果高度一致。通过改变激发通量，我们改变了电子-电子散射与电子-声子散射在初始分布弛豫中的相对重要性。增加激发通量会导致非共线电子-电子散射增强和赝自旋极化降低，尽管向上散射的电子仍保留一定程度的极化。这些详细的动量分辨电子动力学展示了高性能时间分辨动量显微技术在二维材料研究中的能力，并可为石墨烯器件的设计提供参考。
英文摘要：
The unique optical properties of graphene, with broadband absorption and ultrafast response, make it a critical component of optoelectronic and spintronic devices. Using time-resolved momentum microscopy with high data rate and high dynamic range, we report momentum-space measurements of electrons promoted to the graphene conduction band with visible light, and their subsequent relaxation. We observe a pronounced non-thermal distribution of nascent photoexcited electrons with lattice pseudospin polarization in remarkable agreement with results of simple tight-binding theory. By varying the excitation fluence, we vary the relative importance of electron-electron vs. electron-phonon scattering in the relaxation of the initial distribution. Increasing the excitation fluence results in increased noncollinear electron-electron scattering and reduced pseudospin polarization, although up-scattered electrons retain a degree of polarization. These detailed momentum-resolved electron dynamics in graphene demonstrate the capabilities of high-performance time-resolved momentum microscopy in the study of 2D materials and can inform the design of graphene devices.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
