  We propose the existence, via analytical derivations, novel phenomenologies,
and first-principles-based simulations, of a new class of materials that are
not only spontaneously optically active, but also for which the sense of
rotation can be switched by an electric field applied to them-- via an induced
transition between the dextrorotatory and laevorotatory forms. Such systems
possess electric vortices that are coupled to a spontaneous electrical
polarization. Furthermore, our atomistic simulations provide a deep microscopic
insight into, and understanding of, this class of naturally optically active
materials.
