Ultrafast Spin Dynamics with TDDFT*

Laser-induced ultrafast spin dynamics can manipulate the magnetic moment of materials on femtosecond timescales, several orders of magnitude faster than traditional methods.

In the past few years, we have applied real-time time dependent density functional theory to study the induced spin dynamics and provide an overdue ab-initio perspective to this problem. We observed two main mechanisms for ultrafast change in local magnetic moments: 1) spin-orbit driven spin-flips[1] leading to ultrafast demagnetization and 2) optical inter-sublattice spin transfer OISTR[2].

OISTR was first predicted in Heusler compounds[2], but appears for a wide range of materials, including anti-ferromagnetic systems where it can be used to switch the material to a transient ferromagnetic state[3].

The signature of OISTR has seen been observed experimentally for several materials including Heusler compounds, Co/Cu interfaces[4], Ni/Pt multilayers, CoPt, and FeNi.

In this talk I will review our findings so far and hope to convince you that ultrafast spin dynamics has been a real success story for TDDFT.

[1] Krieger et al. J. Chem. Theory and Comput. 11, 3870 (2015)
[2] Elliott et al. Sci. Rep. 6, 38911 (2016)
[3] Dewhurst et al. Nano Lett. 18, 1842 (2018)
[4] Chen et al. PRL. 122, 067202 (2019)

In collaboration with: Peter Elliott<span style="font-size:10.8333px"> (</span>Max Born Institute Berlin, Berlin, Germany), J.K. Dewhurst<span style="font-size:10.8333px"> (</span>Max Planck Inst of Microstructure Physics), Eberhard K Gross<span style="font-size:10.8333px"> (</span>ritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem), Sangeeta Sharma<span style="font-size:10.8333px"> (</span>Max Born Institute Berlin, Berlin, Germany)