Ranju Dalal et al., “Signatures of moire intralayer biexcitons and exciton-phason coupling in WSe2/WS2,” arXiv:2601.03045 (2026).

Summary: Exploring how light, electrons, and crystal lattices interact is key to understanding new phases in condensed-matter physics. Moiré superlattices, created by stacking and twisting atomic layers (analogous to rotating two wire grids), offers a way to modify these interactions. By shining lasers in a specialized way, we uncover long-lived moiré intralayer excitons. We further reveal long-lasting moiré intralayer intervalley biexcitons (four-particle state) trapped within the twisted pattern. Remarkably, our measurements capture signatures of excitons “dancing” with phasons, which are very low energy lattice vibrations in superlattices. This “dance” results in twist-angle-dependent gigahertz oscillations in exciton dynamics. Our experimental approach turns twisted materials into a tuneable platform for studying diverse low-energy collective modes and developing the next generation of advanced quantum technologies.