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O: Fachverband Oberflächenphysik

O 56: 2D Materials beyond Graphene

O 56.9: Poster

Dienstag, 21. März 2017, 18:30–20:30, P2-EG

Near-surface dynamics of hot carriers in 2H-MoS₂: momentum-dependent relaxation and spin- and valley-polarized excitation — •Hauke Beyer, Petra Hein, Gerald Rohde, Ankatrin Stange, Marcel Behrendt, Kerstin Hanff, Lexian Yang, Kai Rossnagel, and Michael Bauer — Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Germany

Time- and angle-resolved photoelectron spectroscopy (trARPES) is employed to study different aspects of ultrafast near-surface carrier dynamics in 2H-MoS₂. Momentum-dependent population and relaxation processes within the conduction-band energy landscape are monitored following photoexcitation with 395  nm laser pulses. Our results indicate that surface-localized defect states play a key role in the final depopulation of the conduction band [1]. Furthermore, we are able to selectively address K and K’ valleys in the trARPES experiment using circularly polarized 590  nm laser pulses owing to the lack of inversion symmetry in the top layer of 2H-MoS₂. Similar to recent trARPES results reported for 2H-WSe₂ [2], dichroism is observed in excited state intensity as well as dynamics.

[1] P. Hein et al., Phys. Rev. B 94, 205406 (2016).

[2] R. Bertoni et al., arXiv:1606.03218.