Regensburg 2022 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 7: Fluctuations, Noise, Magnetotransport, and Related Topics

TT 7.7: Vortrag

Montag, 5. September 2022, 16:45–17:00, H23

Optical dipole orientation of interlayer excitons in MoSe₂-WSe₂ heterostacks — •Mirco Troue¹, Lukas Sigl¹, Manuel Katzer², Malte Selig², Florian Sigger¹, Jonas Kiemle¹, Johannes Figueiredo¹, Mauro Brotons-Gisbert³, Brian Gerardot³, Andreas Knorr², Ursula Wurstbauer⁴, and Alexander Holleitner¹ — ¹TU Munich — ²Technical University Berlin — ³Heriot-Watt University — ⁴University of Münster

Transition metal dichalcogenide monolayers exhibit strong light-matter interactions, which promotes them as ideal candidates for novel 2D optoelectronic applications. A vertical stacking into van der Waals heterostacks leads to the formation of long-lived interlayer excitons in adjacent layers. We present the far-field photoluminescence intensity distribution of interlayer excitons in MoSe₂-WSe₂ heterostacks as measured by back focal plane imaging in the temperature range between 1.7K and 20K. An analytical model describing the emission pattern from a dielectric heterostructure is used to obtain the relative contributions of the in- and out-of-plane transition dipole moments associated with the interlayer exciton photon emission. We determine the transition dipole moments for all observed interlayer exciton transitions to be (99 ± 1)% in-plane for R- and H-type stacking, independent of the excitation power and therefore the density of the exciton ensemble in the experimentally examined range. Moreover, we discuss the limitations of the presented measurement technique to observe correlation effects for many-body states in dense ensembles of interlayer excitons.