Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 45: Ultrafast Electron Dynamics at Surfaces and Interfaces IV
O 45.3: Vortrag
Mittwoch, 20. März 2024, 11:00–11:15, MA 041
Probing electron-hole Coulomb correlations in the exciton landscape of a twisted semiconductor heterostructure — •Jan Philipp Bange1, David Schmitt1, Wiebke Bennecke1, Giuseppe Meneghini2, AbdulAziz AlMutairi3, Daniel Steil1, Sabine Steil1, R. Thomas Weitz1, G. S. Matthijs Jansen1, Stephan Hofmann3, Samuel Brem2, Ermin Malic2, Marcel Reutzel1, and Stefan Mathias1 — 1Georg-August-Universität Göttingen, I. Physikalisches Institut, Germany — 2Philipps-Universität Marburg, Germany — 3University of Cambridge, U.K.
An exciton is a two-particle correlated state between an electron and a hole. In the type-II band aligned WSe2/MoS2 heterostructure, interlayer excitons can be formed after the resonant excitation of the WSe2 intralayer excitons. In this process, the exciton’s electron transfers across the interface while the hole remains rigid in the MoS2 layer [1]. Moreover, the inverted process is possible: After exciting MoS2 intralayer excitons, charge transfer of the exciton’s hole across the interface leads to the formation of interlayer excitons. In this case, the exciton’s electron remains rigid in WSe2.
Here, we employ time-resolved momentum microscopy to study the ultrafast hole-transfer mechanism. Interestingly, we find a distinct photoemission feature that can only be described when considering the break-up of the Coulomb correlation between the exciton’s electron and hole during the photoemission process [2].
[1] Schmitt, Bange et al., Nature 608, 499-503 (2022).
[2] Bange et al., arXiv:2303.17886 (2023).
Keywords: Ultrafast exciton dynamics; Hole-transfer; time-resolved ARPES; momentum microscopy; Coulomb correlation