Experimental investigation of the ratchet effect in a two-dimensional electron system with broken spatial inversion symmetry

We report on the experimental evidence of directed electron transport, induced by external linear-polarized microwave irradiation, in a two-dimensional spatially periodic asymmetrical system called ratchet. The broken spatial symmetry was introduced in a high mobility two-dimensional electron gas (2DEG) based on AlGaAs/GaAs heterojunction by patterning an array of artificial semidisks-shaped antidots. We show that the direction of the transport is efficiently changed by the microwave polarization. The dependence of the effect on magnetic field and temperature is investigated. This represents a significant step toward the realization of microwave detectors and current generators.