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Ultrafast local demagnetization in 𝑑 6 systems via driven Jahn-Teller distortions

van Veenendaal, Michel [Northern Illinois Univ., DeKalb, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)] (ORCID:0000000348535904)
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Abstract

Ultrafast control of spin orientations without relying on highly nonequilibrium electron distributions offers a new pathway for femtosecond spintronics. It is shown that excitation of specific vibronic modes can drive a substantial demagnetization of a local moment relative to the magnetization axis, while preserving its total spin quantum number. Using a fully quantum many-body treatment of a local 𝑆=2 (𝑑 6 ) many-body spin coupled to a driven Jahn-Teller mode with quantum dissipation, we find that the projected spin can be strongly reduced via a Jahn-Teller-induced π‘₯⁒𝑦↑→𝑦⁒𝑧/𝑧⁒π‘₯↓ transition, which occurs without additional Coulomb exchange cost. The excited state subsequently relaxes back to its original electronic configuration with a rotated spin direction, enabling spin reorientation without generating a large net angular momentum in the electronic subsystem.

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75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITYJahn-Teller effectMagnetismStrongly correlated systemsUltrafast demagnetizationVibronic effects

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van Veenendaal, Michel [Northern Illinois Univ., DeKalb, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)] (ORCID:0000000348535904). 2026-05-14. Ultrafast local demagnetization in 𝑑 6 systems via driven Jahn-Teller distortions. https://doi.org/10.1103/49qf-1zhv

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