Vortices in 2D Colloids

Particles and molecules composing real materials generally contain anisotropic properties such as a spin or an electric dipole. To understand their roles in material phase states, we observed colloidal crystals comprised of Janus colloids whose anisotropic properties can be controlled. Here, we found a BKT transition by tuning an interparticle interaction and could see dynamics of topological defects in real time. We think that this model system can eventually give an insight to apprehend roles of molecular and atomic orientational dynamics in 2D crystal phases.