Physicists Use Light to Reveal Motion Inside Electron Wigner Crystals

A joint effort by scientists at the University of Basel and the Technical University of Munich has introduced a light-based technique to study the elusive Wigner crystal, a state where electrons form a regular lattice instead of moving independently. Using a monolayer of tungsten diselenide cooled to just a few degrees above absolute zero, they measured reflected light and identified novel optical features linked to hybrid quasiparticles known as Wigner crystal polarons.

These polarons arise from the interaction of optically generated excitons with the collective electron motion, providing a sensitive probe of both the crystal structure and its internal dynamics. First-author Lujun Wang and colleague Ferdinand Menzel carried out the experiments, while Professor Michael Knap’s theory group modeled the observations. The findings suggest that atomically thin semiconductors can serve as powerful platforms for exploring strongly correlated electron systems, potentially advancing our understanding of complex quantum materials.