We report on 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 based on AlGaAs/GaAs heterojunction, by patterning an array of artificial semi-discs-shaped antidots. We show that the direction of the transport is efficiently changed by microwave polarization. The dependence of the effect on magnetic field and temperature is investigated. This represents a significant step towards the realization of new microwave detectors and current generators.
Tunnelling between two-dimensional electron systems has been studied in the magnetic field perpendicular to the systems planes. The satellite conductance peaks of the main resonance have been observed due to the electron tunnelling assisted by the el
astic scattering on impurities in the barrier layer. These peaks are shown to shift to the higher voltage due to the Coulomb pseudogap in the intermediate fields. In the high magnetic fields the pseudogap shift is disappeared.
