Numerical Study of Photo-Induced Dynamics in Double-Exchange Model

TL;DR

This study numerically investigates how photo-irradiation affects spin and charge dynamics in a double-exchange model, revealing rapid correlation collapse and new spectral features, with implications for manganite experiments.

Contribution

It provides a detailed numerical analysis of photo-induced dynamics in the double-exchange model using advanced computational methods, highlighting the role of localized spins and photon density.

Findings

Charge and antiferromagnetic correlations collapse rapidly after photon irradiation.

New spectral peaks appear inside the insulating gap post-irradiation.

Spin dynamics are significantly influenced by photon density, especially at low densities.

Abstract

Photo-induced spin and charge dynamics in double-exchange model are numerically studied. The Lanczos method and the density-matrix renormalization-group method are applied to one-dimensional finite-size clusters. By photon irradiation in a charge ordered (CO) insulator associated with antiferromagnetic (AFM) correlation, both the CO and AFM correlations collapse rapidly, and appearances of new peaks inside of an insulating gap are observed in the optical spectra and the one-particle excitation spectra. Time evolutions of the spin correlation and the in-gap state are correlated with each other, and are governed by the transfer integral of conduction electrons. Results are interpreted by the charge kink/anti-kink picture and their effective motions which depend on the localized spin correlation. Pump-photon density dependence of spin and charge dynamics are also studied. Roles of spin degree of freedom are remarkable in a case of weak photon density. Implications of the numerical results for the pump-probe experiments in perovskite manganites are discussed.