Superradiant charge density waves in a driven hybrid cavity-matter system

Optical cavities enable strong, long-range, light-matter interactions that drive collective ordering, such as superradiant self-organization in ultracold atomic gases. Extending these ideas to solid-state electron systems could enable continuous-wave optical control of electronic order, but is impeded by the mismatch between optical wavelengths and electronic length scales. Here, we propose a platform for realizing superradiant charge density waves in doped, driven transition-metal dichalcogenides coupled to an optical cavity. A nanoscale grating generates electric fields at large in-plane optical momenta, allowing cavity photons to couple efficiently to electronic density fluctuations through exciton-polaron processes. Using a linear-stability analysis, we determine the threshold for superradiant ordering and map out the driven phase diagram. We show that matching the grating periodicity to the enhanced electronic density fluctuations—such as those near Wigner crystallization—lowers the required pump intensity. Our results establish a route toward cavity-controlled electronic order in quantum materials.