In this work, published in Physical Review Letters, we demonstrate that the polarization of light is changed dramatically when its energy resonates with the polaron-hopping energy of self-trapped electrons. In the presence of spin-orbit coupling, the self-trapped hopping electron may reverse its spin producing a large gyrotropic effect, which is observed close to room temperature. The effect is observed in La2∕3Ca1∕3MnO3 thin films and, plausibly, should be present in other manganites.
Since straining this kind of materials can change the polaron concentration, our finding suggests a route to mechanical or electro-mechanical control of the magneto-optical effect, paving the way to unconventional magnetoelectric effects.
This work has been highlighted with a Synopsis on the Physics website:
http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.117.026401