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Three-stage ultrafast demagnetization dynamics in a monolayer ferromagnet
Na Wu1,2, Shengjie Zhang1,2, Daqiang Chen1,2
1Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
Nature Communications
|March 30, 2024
Summary
Ultrafast laser pulses demagnetize Fe3GeTe2 in three stages, revealing coupled spin and lattice dynamics. This study advances understanding of ultrafast demagnetization and angular momentum transfer in magnetic materials.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Ultrafast Spectroscopy
Background:
- Ultrafast demagnetization using intense laser pulses offers potential for novel magneto-optical devices.
- Capturing coupled spin-electron and spin-lattice dynamics during demagnetization presents significant challenges.
Purpose of the Study:
- To investigate the photoinduced ultrafast demagnetization process in the prototype monolayer ferromagnet Fe3GeTe2.
- To resolve the multi-stage dynamics and understand the interplay between spin, electron, and lattice degrees of freedom.
Main Methods:
- Time-resolved spectroscopy to probe ultrafast demagnetization.
- Analysis of a three-stage demagnetization process.
- Investigation of coherent phonon dynamics and nonlinear phonon couplings.
Main Results:
- Observed ultrafast demagnetization on a 100 fs timescale.
- Identified light-induced coherent A1g phonon dynamics coupled to spin dynamics (200-800 fs).
- Revealed chiral lattice vibrations driving spin precession and nonadiabatic effects causing phonon hardening and suppressed spin-lattice couplings.
Conclusions:
- Advanced understanding of dynamic charge-spin-lattice couplings in ultrafast demagnetization.
- Provided evidence for angular momentum transfer between phonon and spin degrees of freedom.
- Highlighted the complex interplay governing demagnetization dynamics in Fe3GeTe2.
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