Non-equilibrium magnetic interactions in strongly correlated systems
Abstract
We formulate a low-energy theory for the magnetic interactions between electrons in the multi-band Hubbard model under non-equilibrium conditions determined by an external time-dependent electric field which simulates laser-induced spin dynamics. We derive expressions for dynamical exchange parameters in terms of non-equilibrium electronic Green functions and self-energies, which can be computed, e.g., with the methods of time-dependent dynamical mean-field theory. Moreover, we find that a correct description of the system requires, in addition to exchange, a new kind of magnetic interaction, that we name "twist exchange", which formally resembles Dzyaloshinskii-Moriya coupling, but is not due to spin-orbit, and is actually due to an effective three-spin interaction. Our theory allows the evaluation of the related time-dependent parameters as well.
Keywords
Cite
@article{arxiv.1212.3671,
title = {Non-equilibrium magnetic interactions in strongly correlated systems},
author = {Andrea Secchi and Sergei Brener and Alexander I. Lichtenstein and Mikhail I. Katsnelson},
journal= {arXiv preprint arXiv:1212.3671},
year = {2013}
}