Bustamante: Nonlinear Phononics: Manipulating Electric and Magnetic Orders through Coherent Phonon Excitations

We investigate the application of nonlinear phononics to manipulate material properties via coherent phonon excitations. In BiFeO3, we achieve simultaneous enhancement of ferroelectric and antiferromagnetic orders by exciting a high-frequency phonon mode with intense MIR pulses. Our theoretical framework illustrates how coherently excited infrared-active phonons can induce nonlinear electric polarizations and magnetizations through nonlinear couplings. Furthermore, we introduce a mechanism termed nonlinear magnonic rectification, which enables the induction of quasistatic magnetization via rectified spin precession in antiferromagnets. These discoveries open new pathways for dynamically controlling electrical and magnetic properties in solid materials.