Monte Carlo simulation of ultrafast nonequilibrium spin and charge transport in iron

Abstract

Spin transport and spin dynamics after femtosecond laser pulse irradiation of iron (Fe) are studied using a kinetic Monte Carlo model. This model simulates spin dependent dynamics by taking into account two interaction processes during nonequilibrium: elastic electron–lattice scattering, where only the direction of the excited electrons changes, and inelastic electron–electron scattering processes, where secondary electrons are generated. An analysis of the spin dependent particle kinetics inside the material shows that a smaller elastic scattering time leads to a larger spatial spread of electrons in the material, whereas generation of secondary electrons extends the time span for superdiffusive transport and increases the spin current density.