Light driven magnetic and topological phase transitions in magnetic topological insulator thin films

The external manipulation of the magnetism in topological materials would be important both for fundamental interests and practical applications. Herein, we predict that topological and magnetic properties in magnetically doped topological insulator thin films can be well tuned by the laser field. With increasing the strength of the circularly polarized laser (CPL), we can observe a topological phase transition in such system. Remarkably, the CPL could even induce the magnetic phase transition driving thin films from ferromagnetism to paramagnetism. Its critical behavior strongly depends on the quantum quenching, indicating that different Curie temperatures can be observed in different time scales and experimental setups. Furthermore, we propose an all-optical transistor device in which the on-off signal from polar Kerr-rotation angel can be controlled by the applying laser field. Our discoveries not only deepen our understanding of the relationship between topology and magnetism in the magnetic topological insulator in the non-equilibrium regime, but also extend optoelectronic device applications in topological materials.