Theory for photoinduced structural phase transitions and their dynamics in a 2-D insulating crystal

We theoretically study non-linear non-equilibrium real-time dynamics of domain formation by photogenerated excitons in a 2-D insulating crystals, and search for successful conditions under which photoinduced structural phase transition (PSPT) occur. Our model is a many-exciton system, coupling strongly with Einstein phonons, and also interacting with a reservoir. Using this model, we numerically calculate its time-evolution dynamics, full-quantum mechanically. It is found that the anisotropy of inter-exciton interactions is essential for a large domain nucleation, and also to make the PSPT successful, as compared with the isotropic cases.