Observation of a light-induced nonohmic current in a toroidal-moment-possessive nanostructure

We report on the first observation of light-induced nonohmic current in a semiconductor nanostructure. The effect is revealed in unbiased asymmetric InAs quantum well under the excitation by far-infrared laser radiation in presence of a tilted magnetic field. It is interpreted in terms of nonzero toroidal moment of the two-dimensional electron gas.