Large-amplitude spin oscillations triggered by nonequilibrium strongly correlated $t_{2g}$ electrons

摘要

Laser-induced ultrafast (fs) magnetization experiments in antiferromagnetshave recently attracted large attention, paving the road for inherently fastspin dynamics in the THz regime without invoking stray fields. The technicalimportance is emphasized by the rising new research field of antiferromagnetic(AFM) spintronics, where superexchange-dominated strongly correlated compoundsprovide an interesting materials playground. An intriguing question is whetherthe Coulomb interaction may be a key to control AFM order on ultrafast timescales. Therefore, we study (de)magnetization processes in a time-dependentmultiorbital Hubbard model, focusing on $t_{2g}$ electrons in a wider dopingrange. Depending on filling, we reveal large-amplitude spin oscillations viainteraction quenches from the antiferromagnetic or paramagnetic state.Nonequilibrium ultrafast spin-orientation effects in prominent correlatedtransition-metal oxides are therefrom predicted.