Dynamical exchange and phase induced switching of a localized molecular spin

We address the dynamics of a localized molecular spin under the influence of external voltage pulses using a generalized spin equation of motion which incorporates anisotropic fields, nonequilibrium conditions, and nonadiabatic dynamics. We predict a recurring 4 pi-periodic switching of the localized spin by application of a voltage pulse of temporal length tau. The switching phenomena can be explained by dynamical exchange interactions, internal transient fields, and self-interactions acting on the localized spin moment.