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

TL;DR

This paper uses Monte Carlo simulations to study ultrafast spin and charge transport in iron after femtosecond laser excitation, revealing how elastic scattering and secondary electron generation influence spin dynamics.

Contribution

It introduces a kinetic Monte Carlo model that accounts for elastic and inelastic electron interactions to analyze nonequilibrium spin transport in iron.

Findings

Smaller elastic scattering time increases electron spatial spread.

Secondary electron generation prolongs spin polarization propagation.

Elastic scattering and secondary electrons significantly impact spin dynamics.

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 neglecting the energy loss, and inelastic electron - electron interaction, where secondary electrons are generated. An analysis of the particle kinetics inside the material shows that a smaller elastic scattering time affects the spin dynamics by leading to a larger spatial spread of electrons in the material, whereas generation of secondary electrons affects the spin transport with a larger time of propagation of homogeneous spin polarization.