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arXiv · 2607.22532

Supermoir\'e-trapped quadrupolar exciton

Anish Kumar·Suman Chatterjee·Kenji Watanabe·Takashi Taniguchi·Kausik Majumdar
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Abstract

Moir\'e-trapped dipolar interlayer exciton in heterobilayers offers a rich platform to explore interaction-driven phenomena. Extending the number of layers to three and beyond leads to highly intriguing multipolar exciton - a superposition state of vertically aligned phase-coherent excitons. However, in experiments, unintentional twist-angle mismatch among layers may degrade the strength and homogeneity of the vertical Coulomb coupling. Here we propose that the supermoir\'e effect in a heterotrilayer comes to the rescue by creating periodic pockets of vertically aligned atomic registries that facilitate the formation of quadrupolar excitons trapped in such pockets. Using WS$_2$/WSe$_2$/WS$_2$ stack, we show interaction between multiple confined levels of the top and bottom moir\'e interfaces, creating electric field tunable multi-level hybridized bright (symmetric) and dark (anti-symmetric) quadrupolar states. Our work underscores the critical role of supermoir\'e effect in quadrupolar excitons. The discovery of reduced sensitivity on precise angle-alignment will ignite exploration of complex excitonic states in multi-layered heterostructures.

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Anish Kumar, Suman Chatterjee, Kenji Watanabe, Takashi Taniguchi, Kausik Majumdar. 2026-07-24. Supermoir\'e-trapped quadrupolar exciton. https://doi.org/10.1021/acs.nanolett.6c03005

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