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O: Fachverband Oberflächenphysik

O 5: Ultrafast Electron Dynamics at Surfaces and Interfaces I

O 5.3: Vortrag

Montag, 18. März 2024, 11:00–11:15, MA 041

Electron Dynamics in the Conduction Band of the van-der-Waals Magnet Cr₂Ge₂Te₆ — •Stephan Schmutzler, Jan Böhnke, Martin Weinelt, and Cornelius Gahl — Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

The electron dynamics in the central region of the Brillouin zone of Cr₂Ge₂Te₂ has been investigated by time-resolved ARPES. Optical excitation with a photon energy of 1.55 eV leads to a transient broadening of the valence band and simultaneously excites an electron population located at 0.7-1.3 eV above the Fermi level. Within 1 ps, this population continuously relaxes towards states at 0.5 eV. Considering their long lifetime of >3 ps, we attribute these states to the conduction band minimum. Our findings are in contrast to theoretical predictions that locate the minimum close to the K-point of the surface Brillouin zone [1,2]. The broad momentum distribution in the conduction band suggests enhanced scattering in the excited material.
[1] D.-Y. Wang et al. Phys. Rev. B 107, 125148 (2023)
[2] Y. F. Li et al., Phys. Rev. B 98, 125127 (2018)

Keywords: CGT; Ultrafast Electron Dynamics; ARPES; Band Structure