Green’s function approach to adiabatic charge-pumping induced by interfacial spin-flip potential

Abstract

In a system without spin–orbit coupling, a precessing magnetization adiabatically pumps to its surrounding materials a spin current that is not accompanied by a pumped charge current. However, a recent study based on the scattering approach suggested that a precessing magnetization can adiabatically pump a charge current as well in the presence of a spin-flip potential at the interface between a ferromagnetic and an adjacent normal metallic layer. We investigate the pumped charge current in this system using the linear response theory and the Green’s function approach. We explicitly show that the pumped charge current does not vanishes in general, and we obtain the expression of the pumped charge current in terms of the spinor Green’s functions. The pumped charge current turns out to be proportional to a charge pumping coefficient, which supports the result obtained from the scattering approach. We provide numerical calculations of the energy level dependence, exchange coupling’s strength dependence, and the ferromagnetic layer thickness dependence of the charge pumping coefficient.