Ultrafast light-driven simultaneous excitation of coherent terahertz magnons and phonons in multiferroic BiFeO3

Of late, magnetoelectric multiferroics have gained tremendous importance because they possess coexisting magnetic and ferroelectric phases, with cross-correlation effects between magnetic and electric degrees of freedom. BiFeO${}_{3}$ stands out as a canonical material in the multiferroics, because it exhibits ferroelectricity and antiferromagnetism at room temperature. Here, the authors demonstrate for the first time that linearly polarized ultrafast light pulse leads to simultaneous excitation of coherent magnon and optical-phonon modes below the few terahertz frequency regime. Excitation of the terahertz magnon and optical phonon could pave the way to developing ultrafast magnetoelectro-optical devices.