Light-induced weak ferromagnetism through nonlinear magnonic rectification

We theoretically prove that a quasistatic magnetization can be induced by the coherent excitation of a chiral phonon mode. Such phonon mode can generate an effective magnetic field that gives way to a transient spin canting in a mechanism we call nonlinear magnonic rectification. This result is an example of light-induced weak ferromagnetism and provides a promising avenue for creating nonequilibrium spin configurations.