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O: Fachverband Oberflächenphysik
O 83: 2D Materials: Electronic Structure and Exitations III (joint session O/HL/TT)
O 83.7: Talk
Thursday, March 20, 2025, 12:00–12:15, H11
Optical excitations in 2H-MoS2 bilayers under pressure — •Jan-Hauke Graalmann1, Paul Steeger2, Rudolf Bratschitsch2, and Michael Rohlfing1 — 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
Theoretical and experimental investigations have shown several changes in the optical spectrum of the 2H-MoS2 bilayer under pressure [1].
By using density functional theory (DFT) and many-body perturbation theory in combination with linear elasticity, our computational investigations show an effective shift of the A exciton under pressure. It is strongly connected to the behavior of the direct band gap at the K point, which shifts in energy under pressure. The direction of this shift depends on the stress condition. While a hydrostatic pressure leads to a blueshift, a suppression of the in-plane contraction, as it appears in diamond anvil cell-experiments due to the interaction between the sample and the substrate, shows a redshift.
Moreover, we observe a similar behavior for the interlayer exciton, whereas the shift rate is smaller than that of the A exciton, which results in a decreasing A-IL splitting for an increasing pressure.
[1] P. Steeger, J. Graalmann et al., Nano Lett., 23, (2023)
Keywords: interlayer exciton; TMDC bilayer; pressure; elasticity theory; diamond anvil cell