Asymmetric Spin Canting and Demagnetization Dynamics Driven by Laser Fields in Two-Dimensional Altermagnets.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41657125.
- Also identified by DOI 10.1021/acs.nanolett.5c04244 and PMC identifier 12922177.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Laser-induced ultrafast magnetization dynamics have been well established in conventional magnets but remain unexplored in altermagnets (AMs). Using real-time time-dependent density functional theory (rt-TDDFT), we demonstrate that laser pulses can drive asymmetric demagnetization dynamics between the two Fe sublattices in the two-dimensional (2D) semiconducting AM, Fe<sub>2</sub>WTe<sub>4</sub>, leading to a photoinduced ferrimagnetic state with a net magnetization of approximately 0.3 μ<sub>B</sub> per unit cell. This metastable magnetization originates from the momentum-dependent spin-splitting characteristic of <i>d</i>-wave AMs, which gives rise to an anisotropic optical intersite spin transfer effect (OISTR). Furthermore, the asymmetric demagnetization is accompanied by non-collinear spin dynamics, resulting in distinct spin canting angles for two Fe sublattices. Importantly, these spin dynamics are tunable by the in-plane polarization angle of the laser field. Our findings provide microscopic insight into the ultrafast control of magnetization in 2D AMs and open new avenues for light-driven manipulation of spin textures in AM systems.