Destabilization of spin-Peierls phase via a charge-spin modulated Floquet state induced by intramolecular vibrational excitation

We demonstrate light-induced control of the spin-Peierls phase in a quasi-one-dimensional molecular solid, K-tetracyanoquinodimethane (TCNQ).
Using phase-locked mid-infrared pulses to excite intramolecular vibrations, we observed charge–spin modulated Floquet states that destabilize the spin-Peierls dimerization.
Time-resolved reflectivity measurements revealed high-frequency oscillations associated with electron- and spin-density modulations synchronized with the vibrational mode.
These results establish intramolecular vibrational excitation as an effective approach for Floquet engineering in molecular solids.

Recommended citation: D. Sakai, T. Yamakawa, H. Ueda, R. Ikeda, T. Miyamoto, and H. Okamoto, “Destabilization of spin-Peierls phase via a charge-spin modulated Floquet state induced by intramolecular vibrational excitation,” *Communications Physics*, vol. 7, no. 1, p. 40, 2024. doi:10.1038/s42005-024-01524-w
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