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HL: Fachverband Halbleiterphysik
HL 9: 2D Materials and Heterostructures: Interlayer Excitons
HL 9.3: Talk
Monday, March 18, 2024, 15:30–15:45, EW 201
Emergent Trion-Phonon Coupling in Atomically Reconstructed MoSe2-WSe2 Heterobilayers — •P. Parzefall1, S. Meier1, Y. Zhumagulov2, M. Dietl1, N. Meier1, J. Lichtenberger1, M. Kempf1, J. Holler1, P. Nagler1, K. Watanabe3, T. Taniguchi3, P. E. Faria JR.2, J. Fabian2, T. Korn4, and C. Schüller1 — 1Institut für Exp. und Angewandte Physik, Uni Regensburg (UR), Germany — 2Institut für Theo. Physik, UR, Germany — 3NIMS, Tsukuba Ibaraki, Japan — 4Institut für Physik, Uni Rostock, Germany
We report about low-frequency Raman studies on atomically-reconstructed MoSe2-WSe2 heterostructures (HS) at cryogenic temperatures. In these experiments, we tune a Ti:Sapphire laser into close resonance to the intralayer excitonic transitions of both, MoSe2 and WSe2, and compare the resulting Raman spectra to the well-known off-resonant case [1]. We detect a low-enery Raman mode, which is observable only at the intralayer trion (X−) resonances. The energy of the emergent Raman mode is close to the interlayer shear mode (ISM) of the HS [1] but it exhibits different polarization selection rules and a lineshape, resembling a Fano-profile.
We interpret our results as follows: The X− gains an
interlayer character via its second electron, which is located in the Q valley and distributed over both layers, and which enables the coupling to the interlayer shear mode.
[1] J. Holler et al., APL 117, 013104 (2020)
[2] S. Meier et al., Phys. Rev. Res. 5 , L032036 (2023)
Keywords: Trion-Phonon Coupling; Heterobilayers; Atomic Reconstruction; Resonant Raman Spectroscopy; Transition metal dichalcogeniode