Understanding spin-lattice interactions in antiferromagnets is one of the most fundamental issues at the core of the recently emerging and booming fields of antiferromagnetic spintronics and magnonics. Recently, coherent nonlinear spin-lattice coupling was discovered in an antiferromagnet which opened the possibility to control the nonlinear coupling strength and thus showing a novel pathway to coherently control magnon-phonon dynamics. Here, utilizing intense narrow band terahertz (THz) pulses and tunable magnetic fields up to 7 T, we experimentally realize the conditions of the Fermi magnon-phonon resonance in antiferromagnetic CoF2. These conditions imply that both the spin and the lattice anharmonicities harvest energy transfer between the subsystems, if the magnon eigenfrequency fm is twice lower than the frequency of the phonon 2fm=fph. Performing THz pump-infrared probe spectroscopy in conjunction with simulations, we explore the coupled magnon-phonon dynamics in the vicinity of the Fermi-resonance and reveal the corresponding fingerprints of an impulsive THz-induced response. This study focuses on the role of nonlinearity in spin-lattice interactions, providing insights into the control of coherent magnon-phonon energy exchange.
@article{arxiv.2308.01052,
title = {Impulsive Fermi magnon-phonon resonance in antiferromagnetic $CoF_{2}$},
author = {Thomas W. J. Metzger and Kirill A. Grishunin and Chris Reinhoffer and Roman M. Dubrovin and Atiqa Arshad and Igor Ilyakov and Thales V. A. G. de Oliveira and Alexey Ponomaryov and Jan-Christoph Deinert and Sergey Kovalev and Roman V. Pisarev and Mikhail I. Katsnelson and Boris A. Ivanov and Paul H. M. van Loosdrecht and Alexey V. Kimel and Evgeny A. Mashkovich},
journal= {arXiv preprint arXiv:2308.01052},
year = {2024}
}