Adiabatic Pumping of Orbital Magnetization by Spin Precession

We propose adiabatic pumping of orbital magnetization driven by coherent spin precession, which enables rectification by converting periodic oscillations into a static signal. The orbital magnetization originates from the adiabatic evolution of valence electrons with a topological bulk contribution expressed as a Chern-Simons form. When the precession cone angle of spin S is small, the resulting magnetization is proportional to S×S[over ˙] and contributes to the magnon Zeeman effect, the energy shift induced by a magnetic field. With a large cone angle, the magnetization can reach its natural unit, e/T, in an antiferromagnetic topological insulator with e as the elementary charge and T as the precession period. This significant magnetization is related to the global properties of the electronic geometric phases in the parameter space spanned by S and momentum k. When the pumped magnetization is inhomogeneous, induced by spin textures or electronic topological phase domains, a dissipationless charge current is also pumped. At last, we discuss the boundary contributions from the spin-driving edge states, which are intricately linked to the gauge-dependent quantum uncertainty of the Chern-Simons form.