Route to minimally dissipative switching in magnets via terahertz phonon pumping

Ultrafast switching of magnetic materials has been shown to be predominantly thermally driven, but excess heating limits the energy efficiency of this process. By employing atomistic spin-lattice dynamics simulations, we show that efficient coherent magnetization switching of an insulating magnet can be triggered by a THz excitation of phonons. We find that switching is driven by excitation near the P point of the phonon spectrum in conditions where spins typically cannot be excited and when manifold k phonon modes are accessible at the same frequency. Our model determines the necessary ingredients for low-dissipative switching and provides insight into THz-excited spin dynamics with a route to energy efficient ultrafast devices.