High optical performance and practicality of active plasmonic devices based on rhombohedral BiFeO3

First principles calculations of electronic and optical properties of multiferroic oxide BiFeO3 are used in combination with a plasmonic device model of optical switch to show that a BiFeO3 based device can have much better performance than devices based on existing materials. This arises from the combination of octahedral tilts, ferroelectricity and G-type antiferromagnetism in BiFeO3 leading to a strong dependence of the optical refractive indices on the orientation with respect to the polarization. A prototype of a plasmonic resonator with an R-BFO thin film layer is used as an example and shows excellent switch and modulation responses. The proposed approach provides potential opportunities to develop high performance nanophotonic devices for optical communication.