Pumping of Orbital Magnetization By Spin Precession in Topological Magnets*

It has been demonstrated that topological states are useful for controlling the spin dynamics of magnets. In this work, the reciprocal process, i.e. the responses of topological phases to dynamically precessing spins, is investigated. The heterostructure of a Z₂ topological insulator and an easy-plane ferromagnet is our initial focus. Studied are the effects of spin precession on topological and magnetic properties. We will discuss the distinctions between edge and bulk contributions. We then turn to an antiferromagnetic topological insulator with parity-time symmetry. The effects of symmetry breaking by spin dynamics are investigated. Specifically, we reveal the physical manifestation of the hidden Yang's monopole at the point of topological phase transition. Experimental signatures of the monopole will be discussed. These results will benefit the dynamical control of the magnetic topological systems on demand.