Superradiant Charge Density Waves in a Driven Cavity-Matter Hybrid

TL;DR

This paper proposes a new platform using optical cavities and nanoscale gratings to induce superradiant charge density waves in doped transition-metal dichalcogenides, enabling cavity-controlled electronic order.

Contribution

It introduces a method to realize superradiant charge density waves in solid-state systems via cavity coupling and nanoscale gratings, expanding cavity QED concepts to quantum materials.

Findings

Threshold for superradiant ordering determined by linear stability analysis.

Tuning grating periodicity reduces pump intensity needed for ordering.

Phase diagram of driven superradiant charge density waves mapped out.

Abstract

Optical cavities enable strong, long-range, light-matter interactions that can drive collective ordering phenomena, 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 (sCDWs) 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 tuning the grating periodicity to match the enhanced electronic density fluctuations - such as those near Wigner crystallization - substantially lowers the required pump intensity. Our results establish a novel route toward cavity-controlled electronic order in quantum materials.