Photoexcitation has been utilized to control quantum matter and to uncover metastable phases far from equilibrium. Among demonstrations to date, the most common is the photo-induced transition from correlated insulators to metallic states; however, the reverse process without initial orders has not been observed. Here, we show ultrafast metal-to-insulator transition in gate-doped WS2/WSe2 and WSe2/WSe2 moir\'e devices using photo-thermionic hole injection from graphite gates. The resulting correlated insulators are metastable, with lifetimes exceeding microseconds. These findings establish an effective mechanism for the ultrafast control of correlated electronic phases in van der Waals heterostructures.
@article{arxiv.2510.21005,
title = {Photoinduced Metal-to-Insulator Transitions in 2D Moir\'e Devices},
author = {Yiliu Li and Esteban Rojas-Gatjens and Yinjie Guo and Birui Yang and Dihao Sun and Luke Holtzman and Juseung Oh and Katayun Barmak and Cory R. Dean and James C. Hone and Nathaniel Gabor and Eric A. Arsenault and Xiaoyang Zhu},
journal= {arXiv preprint arXiv:2510.21005},
year = {2025}
}