Polarized-microwave control of directed transport in a 2D electron gas with artificial asymmetrical scatterers

The directed electron transport, driven by external linear-polarized microwave irradiation, in a two-dimensional spatially periodic asymmetrical system called “ratchet” has been studied experimentally. 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 semidiscs-shaped scatterers (antidots). A directed electric current of few μA was observed in the “ratchet” antidot lattice under microwave irradiation (of few μW) in the absence of any external current applied to the sample. The signal was recorded as a function of magnetic field, temperature, microwave power and polarization.