1. X-ray Free Electron Laser Studies of Electron and Phonon Dynamics of Graphene Adsorbed on Copper
- Author
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Ogasawara, Hirohito, Wang, Han, Gladh, Jörgen, Gallo, Alessandro, Page, Ralph, Voss, Johannes, Luntz, Alan, Diesen, Elias, Abild-Pedersen, Frank, Nilsson, Anders, Soldemo, Markus, Zajac, Marc, Attar, Andrew, Chen, Michelle E., Cho, Sang Wan, Katoch, Abhishek, Kim, Ki-Jeong, Kim, Kyung Hwan, Kim, Minseok, Kwon, Soonnam, Park, Sang Han, Ribeiro, Henrique, Sainio, Sami, Wang, Hsin-Yi, Yang, Cheolhee, and Heinz, Tony
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics ,Physics - Chemical Physics - Abstract
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., Comment: 22 pages, 8 Figures including Supplementary Material
- Published
- 2022