Dynamical coupling and separation of multiple degrees of freedom in a photoexcited double-exchange system

TL;DR

This paper develops a microscopic theory and simulations to understand ultrafast photo-induced spin and charge dynamics in a coupled system, revealing distinct short- and long-time behaviors that differ from traditional equilibrium models.

Contribution

It introduces a detailed microscopic framework and real-time simulation methods to analyze the ultrafast dynamics in a spin-charge coupled system, highlighting the separation of degrees of freedom.

Findings

Electron motion dominates short-time charge-spin dynamics.

Long-time spin relaxation decouples charge dynamics from spin changes.

Results contrast with conventional equilibrium double-exchange models.

Abstract

We present a theory of ultrafast photo-induced dynamics in a spin-charge coupled system, motivated by pump-probe experiments in perovskite manganites. A microscopic picture for multiple dynamics in spin and charge degrees is focused on. Real-time simulations are carried out by two complimentary methods. Our calculation demonstrates that electron motion governs a short-time scale where charge and spin dynamics are combined strongly, while, in a long-time scale controlled by spin relaxation, charge sector does not follow remarkable change in spin sector. Present results are in contrast to a conventional double-exchange picture in equilibrium states.