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O: Fachverband Oberflächenphysik
O 16: Ultrafast Electron Dynamics at Surface and Interfaces II
O 16.5: Vortrag
Montag, 27. März 2023, 16:15–16:30, TRE Phy
Direct observation of light-induced ultrafast currents in black phosphorus — •Maciej Dendzik1,2, Andrea Marini3, Samuel Beaulieu2, Shuo Dong2, Tommaso Pincelli2, Julian Maklar2, R. Patrick Xian2, Enrico Perfetto3,4, Martin Wolf2, Gianluca Stefanucci4,5, Ralph Ernstorfer2, and Laurenz Rettig2 — 1KTH Royal Institute of Technology, Stockholm, Sweden — 2Fritz Haber Institute of the Max Planck Society, Berlin, Germany — 3CNR-ISM, Rome, Italy — 4Tor Vergata University of Rome, Rome, Italy — 5INFN, Rome, Italy
Understanding intricate details of light-matter interaction on the femtosecond timescale is at the heart of modern photonics and optoelectronics. However, fundamental coupling between charge carriers response and corresponding induced electromagnetic fields upon an ultrafast optical excitation remain largely unexplored in many quantum materials. Here, we present an experimental time- and momentum-resolved photoemission study of black phosphorus (BP) combined with state-of-the-art simulations of ultrafast carrier dynamics and induced fields. We find dramatically different electron dynamics following excitation by light polarized along the zigzag and armchair directions which we associate with a difference in initial population momentum distributions. Remarkably, we observe a sub-picosecond population imbalance of excited carriers with opposite momenta, which correspond to the generation of transient in-plane currents. The results provide a comprehensive picture of the ultrafast carrier dynamics in BP and pave the way for novel applications in optoelectronics or quantum computing.