Laser induced quasicrystalline order in charge stabilised colloidal systems

We have studied the ordering of a two dimensional charge stabilised colloidal system in the presence of a stationary one dimensionally modulated laser field formed by the superposition of two modulations with wavevectors $q_0 \tau$ and $q_0/\tau$, where $q_0$ is the wavevector corresponding to the first peak of the direct correlation function of the unperturbed liquid, and $\tau$ is the golden mean. In the framework of the Landau-Alexander-McTague theory we find that a decagonal quasicrystalline phase is stabler than the liquid or the triangular lattice in certain regions of the phase diagram. Our study also shows a reentrant melting phenomena for larger laser field strengths. We find that the transition from the modulated liquid to the quasicrystalline phase is continuous in contrast to a first order transition from the modulated liquid to the triangular crystalline phase.