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arXiv · 2503.19883

Quadrupolar and Dipolar Excitons in Bilayer 2$H$-MoSe$_2$

Shun Feng·Aidan J. Campbell·Bibi Mary Francis·Hyeonjun Baek·Takashi Taniguchi·Kenji Watanabe·Iann C. Gerber·Brian D. Gerardot·Mauro Brotons-Gisbert
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Abstract

We report the experimental observation of quadrupolar exciton states in the reflectance contrast spectrum of 2$H$-stacked bilayer MoSe$_2$. The application of a vertical electric field results in a quadratic energy redshift of these quadrupolar excitons, in contrast to the linear energy splitting observed in the coexisting dipolar excitons within the bilayer MoSe$_2$. We perform helicity-resolved reflectance contrast measurements to investigate the spin and valley configurations of the quadrupolar exciton states as a function of applied vertical electric and magnetic fields. Comparing our results with a phenomenological coupled-oscillator model indicates that the electric- and magnetic-field dependence of the quadrupolar exciton states can be attributed to the intravalley and intervalley hybridization of spin-triplet interlayer excitons with opposite permanent dipole moments, mediated by interlayer hole tunneling. These results position naturally stacked MoSe$_2$ bilayers as a promising platform to explore electric-field-tunable many-body exciton phenomena.

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Shun Feng, Aidan J. Campbell, Bibi Mary Francis, Hyeonjun Baek, Takashi Taniguchi, Kenji Watanabe, Iann C. Gerber, Brian D. Gerardot, Mauro Brotons-Gisbert. 2025-03-25. Quadrupolar and Dipolar Excitons in Bilayer 2$H$-MoSe$_2$. https://doi.org/10.1103/physrevlett.134.166901

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