We demonstrate evidence of correlated magnetism for exciton-polaritons in a MoSe2/WS2 moir\'e heterostructure with near-parallel alignment subject to electron doping. In our experiments, interactions between electrons and moir\'e excitons are controlled electrostatically by field-effect doping, and the polaritonic regime of strong light-matter coupling is established in an open cryogenic microcavity. Remarkably, at filling fractions around one electron per moir\'e cell, we observe drastic and nonlinear enhancement of the effective polariton Land\'e factor as a hallmark of correlated magnetism, which is cavity-controlled via resonance tuning of light and matter polariton constituents. Our work establishes moir\'e van der Waals heterostructures as an outstanding platform for studies of correlated phenomena in the presence of strong light-matter coupling and many-body phases of lattice-ordered excitons, charges and spins.
@article{arxiv.2405.12698,
title = {Correlated magnetism of moir\'e exciton-polaritons on a triangular electron-spin lattice},
author = {Johannes Scherzer and Lukas Lackner and Bo Han and Borislav Polovnikov and Lukas Husel and Jonas Göser and Zhijie Li and Jens-Christian Drawer and Martin Esmann and Christoph Bennenhei and Falk Eilenberger and Kenji Watanabe and Takashi Taniguchi and Anvar S. Baimuratov and Christian Schneider and Alexander Högele},
journal= {arXiv preprint arXiv:2405.12698},
year = {2024}
}