Professor Wu’s research group finds surface states in a topological insulator can modify magnetism in a neighboring magnetic insulator.

Magnetic ordering in a magnetic insulator can break the time-reversal symmetry of topological surface states in a neighboring topological insulator; such symmetry breaking can result in several intriguing quantum phenomena, as demonstrated by recent experiments. Conversely, the surface states in the topological insulator may also impact the magnetism in the magnetic insulator, but such effects are still largely unexplored. Professor Wu’s group, in collaboration with Professor Samarth’s group at Penn State, found that topological surface states in a topological insulator can induce a perpendicular anisotropy, reduce the gyromagnetic ratio, and enhance damping in a neighboring magnetic insulator thin film. This work demonstrates a new approach for control of magnetism. The results have been featured in a paper, with Dr. Tao Liu being the first author, that has been published in Physical Review Letters on July 1, 2020. Read the full paper here.