Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Poster 1

HL 25.14: Poster

Mittwoch, 7. September 2022, 18:00–20:00, P2

Assigning excitonic transitions in reconstructed MoSe₂-WSe₂ heterostacks — •Christos Paspalides¹, Mirco Troue¹, Lukas Sigl¹, Johannes Figueiredo¹, Manuel Katzer², Malte Selig², Florian Sigger¹, Roland Gillen³, Jonas Kiemle¹, Andreas Knorr², Ursula Wurstbauer⁴, and Alexander Holleitner¹ — ¹TU Munich — ²Technische Universität Berlin — ³Friedrich-Alexander-Universität Erlangen-Nürnberg — ⁴University of Münster

Transition metal dichalcogenide monolayers exhibit strong light-matter interactions, which promotes them as ideal candidates for novel 2D optoelectronic applications. The vertically stacked Van der Waals heterostacks facilitate the emergence of a type-II band alignment, which leads to the formation of long-lived interlayer excitons. We present g-factors for three distinct interlayer exciton emissions in MoSe₂-WSe₂ heterostacks measured up to 9 T. Theoretical considerations including density functional theory lead to the assignment of the characteristic emission lines to optical transitions inside an atomically reconstructed H-type heterostack with a near-zero twist-angle. Here, the H_h^h atomic registry is able to fill sizable commensurate domains within the reconstructed lattice while the corresponding selection rules are found to govern the optical response of the system.

Following the attribution of the interlayer exciton emissions, we provide a deeper insight into the effect of atomic reconstruction in MoSe₂-WSe₂ heterostacks and discuss the possibility for a macroscopic occupation of the ground-state leading to unique many-body effects of interlayer excitons in such systems.