Berlin 2024 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 9: 2D Materials and Heterostructures: Interlayer Excitons
HL 9.11: Vortrag
Montag, 18. März 2024, 17:45–18:00, EW 201
Pressure Dependence of Intra- and Interlayer Excitons in 2H-MoS2 Bilayers — •Jan-Hauke Graalmann1, Paul Steeger2, Robert Schmidt2, Ilya Kupenko3, Carmen Sanchez-Valle3, Philipp Marauhn1, Thorsten Deilmann1, Steffen Michaelis de Vasconcellos2, Michael Rohlfing1, and Rudolf Bratschitsch2 — 1University of Münster, Institute of Solid State Theory, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany — 2University of Münster, Institute of Physics and Center for Nanotechnology, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany — 3University of Münster, Institute of Mineralogy, Corrensstr. 24, 48149 Münster
The optical spectrum of the MoS2 bilayer changes under pressure as theoretical and experimental studies have shown [1].
Our computational investigations of the structural, electronic and optical properties are based on elasticity theory, DFT, GdW and the Bethe-Salpeter equation. The stress conditions in our diamond anvil cell experiment result in an effective shift of the excitation energy of the A exciton towards higher energies with increasing pressure. This shift corresponds strongly to the behavior of the direct band gap at the K point. Due to a growing valence band splitting for increasing pressures, the interlayer exciton shows a smaller shift. In total, the A-IL energy splitting decreases under pressure.
Furthermore, the theoretical reproduction of the experimental results shows a suppression of the transfer of hydrostatic pressure due to the interaction between the bilayer and the substrate.
[1] P. Steeger, J.-H. Graalmann et al., Nano Lett., 23, (2023)
Keywords: MoS2 bilayer; interlayer exciton; high pressure; diamond anvil cell; elasticity theory