论文标题
X射线免费电子激光研究，对铜上吸附的石墨烯的电子和声子动力学
X-ray Free Electron Laser Studies of Electron and Phonon Dynamics of Graphene Adsorbed on Copper
论文作者
论文摘要
我们报告了在无PAL电子激光器上进行的光学泵送和X射线吸收光谱实验，该实验直接探测了在飞秒方面吸附在铜上的石墨烯单层的电子动力学。通过分析Ab-Initio理论的结果，我们推断石墨烯的激发是由光学激光脉冲在铜中产生的热电子孔对的间接激发所主导的。但是，一旦在石墨烯中产生了激发，它的衰减就遵循了类似的路径，与以前对半导体吸附的石墨烯的研究相似，i。 SCOPS快速激发（强烈耦合的光子声子）和最终的热化。铜中热电子孔对的寿命可能控制石墨烯电子激发的寿命。
We report optical pumping and X-ray absorption spectroscopy experiments at the PAL free electron laser that directly probe the electron dynamics of a graphene monolayer adsorbed on copper in the femtosecond regime. By analyzing the results with ab-initio theory we infer that the excitation of graphene is dominated by indirect excitation from hot electron-hole pairs created in the copper by the optical laser pulse. However, once the excitation is created in graphene, its decay follows a similar path as in many previous studies of graphene adsorbed on semiconductors, i e. rapid excitation of SCOPS (Strongly Coupled Optical Phonons) and eventual thermalization. It is likely that the lifetime of the hot electron-hole pairs in copper governs the lifetime of the electronic excitation of the graphene.
