Floquet engineering of magnetism in topological insulator thin films

Dynamic manipulation of magnetism in topological materials is demonstrated here via a Floquet engineering approach using circularly polarized light. Increasing the strength of the laser field, besides the expected topological phase transition (PT), the magnetically doped topological insulator thin film also undergoes a magnetic PT from ferromagnetism to paramagnetism, whose critical behavior strongly depends on the quantum quenching. In sharp contrast to the equilibrium case, the non-equilibrium Curie temperatures vary for different time scale and experimental setup, not all relying on change of topology. Our discoveries deepen the understanding of the relationship between topology and magnetism in the non-equilibrium regime and extend optoelectronic device applications to topological materials.

Automated summary

In this study, the manipulation of magnetism in topological materials is demonstrated using circularly polarized light through a Floquet engineering approach. With the increase of the laser field, besides the expected topological phase transition, a magnetic phase transition from ferromagnetism to paramagnetism is observed in the magnetically doped topological insulator thin film, whose critical behavior strongly depends on the quantum quenching. Unlike the equilibrium case, the non-equilibrium Curie temperatures vary for different time scales and experimental setups, not all relying on the change of topology. Our findings deepen the understanding of the relationship between topology and magnetism in the non-equilibrium regime and extend the optoelectronic device applications to topological materials.