Room temperature valley coherence in monolayer WSe2 mediated by chiral nematic liquid crystal

Hassan Lamsaadi; Andrea Balocchi; Aurélien Cuche; Hugo Lourenco Martins; Vincent Paillard; Sébastien Weber; Jean Marie Poumirol; Gonzague Agez

arXiv · 2607.01098

Room temperature valley coherence in monolayer WSe2 mediated by chiral nematic liquid crystal

Hassan Lamsaadi·Andrea Balocchi·Aurélien Cuche·Hugo Lourenco Martins·Vincent Paillard·Sébastien Weber·Jean Marie Poumirol·Gonzague Agez

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Abstract

Valley coherence refers to a phase-coherent superposition of inequivalent momentum valleys, in which quantum information can be encoded in the relative valley phase. Chiral nematic liquid crystals, by imposing a flip of the spin angular momentum upon light reflection, provide an effective photonic environment for optically coupling excitons of the K and K' valleys in monolayer semiconducting transition-metal dichalcogenides. We experimentally demonstrate that using such liquid crystal as a substrate, it is possible through nearfield interaction to engineer a room temperature mechanism for inducing the intervalley coupling. Our results show that this approach provides a simple and scalable route toward valleytronic functionalities based on controlled coherent emission from valleys with opposite Berry curvature.

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Hassan Lamsaadi, Andrea Balocchi, Aurélien Cuche, Hugo Lourenco Martins, Vincent Paillard, Sébastien Weber, Jean Marie Poumirol, Gonzague Agez. 2026-07-01. Room temperature valley coherence in monolayer WSe2 mediated by chiral nematic liquid crystal. https://arxiv.org/abs/2607.01098

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