A device having a dipolar ring surrounding an interior region that is disposed asymmetrically on the ring. The dipolar ring generates a toroidal moment switchable between at least two stable states by a homogeneous field applied to the dipolar ring in the plane of the ring. The ring may be made of ferroelectric or magnetic material. In the former case, the homogeneous field is an electric field and in the latter case, the homogeneous field is a magnetic field.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
This invention was made with Government support under the terms of Grant No. DE-FG02-05ER46188 awarded by the Department of Energy, Grant No. N00014-04-1-0413 awarded by the Office of Naval Research, Grant Nos. DMR-0701958, DMR-0404335 and DMR-0080054(C-SPIN) awarded by the National Science Foundation and MRI Grant Nos. 0421099 and 0722625 from the National Science Foundation. The Government has certain rights in the invention.