Janus Colloidal Crystal, a New Model System for Spin Ice and Glass

Questions like the dynamics of magnetic monopole in spin ice and the translation -rotation coupling in molecular glass have long puzzled scientists in different communities, mainly because it is hard to monitor the dynamics of these systems on microscopic level. Here we try to address these questions using Janus colloidal crystals, in which both the translational and rotational motions of particles can be tracked by video microscopy and the particle interaction can be finely tuned by electric field. as one of the results, we find that glasslike dynamics for rotational motion appears when the area fraction is so high that the system is crystalline. Our experimental system paves the way for modeling a wide range of phenomenon in spin ice and molecular glasses.