An important vision of modern magnetic research is to use antiferromagnets as controllable and active ultrafast components in spintronic devices. Hematite is a promising model material in this respect because its pronounced Dzyaloshinskii-Moriya interaction leads to the coexistence of antiferromagnetism and weak ferromagnetism. Here, we use femtosecond laser pulses to drive terahertz spin currents from hematite into an adjacent Pt layer. We find two contributions to the generation of the spin current with distinctly different dynamics: the impulsive stimulated Raman scatting that relies on the antiferromagnetic order and the ultrafast spin Seebeck effect that relies on the net magnetization. The total THz spin current dynamics can thus be manipulated by a medium-strength magnetic field. The controllability of the THz spin current achieved in hematite opens the pathway toward controlling the exact spin current dynamics from ultrafast antiferromagnetic spin sources.
@article{arxiv.2209.10175,
title = {Manipulating THz Spin Current Dynamics by the Dzyaloshinskii-Moriya Interaction in Antiferromagnetic Hematite},
author = {Hongsong Qiu and Tom Sebastian Seifert and Lin Huang and Yongjian Zhou and Zdenek Kaspar and Caihong Zhang and Jingbo Wu and Kebin Fan and Qi Zhang and Di Wu and Tobias Kampfrath and Cheng Song and Biaobing Jin and Jian Chen and Peiheng Wu},
journal= {arXiv preprint arXiv:2209.10175},
year = {2022}
}