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arXiv · 2609.01149

Probing Nonlinear Interactions of Dipolar Interlayer Excitons in MoSe$_2$/WSe$_2$ Heterobilayers

Sai Shradha·Luc F. Oswald·Md Tarik Hossain·Lukas Krelle·Nicole Engel·Axel Printschler·Julian Führer·Honey Jayeshkumar Shah·Daria I. Markina·Kenji Watanabe·Takashi Taniguchi·Andrey Turchanin·Bernhard Urbaszek
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Abstract

Interlayer excitons in transition-metal dichalcogenide heterobilayers possess intrinsic out-of-plane dipole moments, providing a platform for investigating exciton-exciton interactions at high densities. Here, we use excitation-energy-dependent photoluminescence excitation (PLE) spectroscopy to probe the nonlinear response of dipolar interlayer excitons in chemical vapor deposition-grown MoSe$_2$/WSe$_2$ heterobilayers. By tuning the excitation energy across intralayer exciton resonances at fixed excitation power, we selectively vary the population injected into the interlayer exciton states. Resonant excitation drives the system into a nonlinear regime, leading to saturation of the interlayer exciton photoluminescence and an apparent broadening of the intralayer $1s$ resonances in the PLE spectra. At the same time, the interlayer exciton emission exhibits a pronounced blueshift, reaching approximately 2.5 meV at 4 K and 1 meV at 75 K. The blueshift increases systematically with the interlayer exciton population and is consistent with a net repulsive exciton-exciton interaction, with contributions from dipole-dipole repulsion in the density regime investigated. Our results establish PLE as a sensitive approach for accessing the nonlinear, high-density regime of interlayer excitons and probing their interactions in van der Waals heterostructures.

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Sai Shradha, Luc F. Oswald, Md Tarik Hossain, Lukas Krelle, Nicole Engel, Axel Printschler, Julian Führer, Honey Jayeshkumar Shah, Daria I. Markina, Kenji Watanabe, Takashi Taniguchi, Andrey Turchanin, Bernhard Urbaszek. 2026-09-01. Probing Nonlinear Interactions of Dipolar Interlayer Excitons in MoSe$_2$/WSe$_2$ Heterobilayers. https://arxiv.org/abs/2609.01149

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