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arXiv · 2405.07304

Giant intrinsic nonlinear phonon-magnon coupling in the antiferromagnet CoF$_2$

M. A. Prosnikov·M. Bal·R. V. Pisarev·P. C. M. Christianen·A. M. Kalashnikova
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Abstract

The observation of strongly coupled lattice and spin dynamics in altermagnet CoF$_2$ is reported. On the background of the expected spin-phonon interaction leading to renormalization of all phonons at the Neel temperature an additional strong coupling between one-magnon excitation and the lowest frequency Raman-active phonon of B1g symmetry was observed and manifested an anomaly in its energy, full width, and intensity at temperature T*=23 K precisely where the frequency of the phonon becomes exactly twice the frequency of the magnon. We assigned this effect to unique magnon-phonon coupling in the form of a two-magnons-one-phonon interaction. The consistent experimental data clearly demonstrate that there is an intrinsic coupling that does not require coherent excitation.

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M. A. Prosnikov, M. Bal, R. V. Pisarev, P. C. M. Christianen, A. M. Kalashnikova. 2024-05-12. Giant intrinsic nonlinear phonon-magnon coupling in the antiferromagnet CoF$_2$. https://arxiv.org/abs/2405.07304

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