Simulating Ultrafast Switching of Magnetic Order using TDDFT

Time dependent density functional theory (TDDFT) has recently[1] been applied to study magnetization dynamics in periodic systems. We identified two mechanisms that can cause changes in the local moment: 1) spin-flips mediated by the spin-orbit interaction[1,2] which contributes to ultrafast demagnetization in simple ferromagnets like Ni,Fe,Co and 2) inter sublattice spin transfer due to optical transitions induced by the applied laser[3]. In this work we look at systems with anti-ferromagnetic coupling and show how the inter sublattice spin transfer can actually cause a switch in the magnetic ordering from anti-ferromagnetic to ferromagnetic.

[1] Laser induced ultrafast demagnetization: an ab-initio perspective, K. Krieger, J.K. Dewhurst, P. Elliott, S. Sharma, and E.K.U. Gross, J. Chem. Theory and Comput. 11, 4870 (2015).
[2] Ultrafast demagnetization in bulk versus thin films: an ab initio study, K. Krieger, P. Elliott, T. Mueller, N. Singh, J.K. Dewhurst, E.K.U. Gross, and S. Sharma, J. Phys. Condens. Matter 29, 224001 (2017).
[3] Ultrafast laser induced local magnetization dynamics in heusler compounds, P. Elliott, T. Mueller, J.K. Dewhurst, S. Sharma, and E.K.U. Gross, Sci Rep 6, 38911 (2016).