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Motivated by the recently discovered microwave-induced ``zero-resistance states in two-dimensional electron systems, we study the microwave photoconductivity of a two-dimensional electron gas (2DEG) subject to a unidirectional static periodic potential. The combination of this potential, the classically strong magnetic field, and the microwave radiation may result in an anisotropic negative conductivity of the 2DEG. Similar to the case of a smooth random potential, two mechanisms contribute to the negative photoconductivity. The displacement mechanism arises from electron transitions due to disorder-assisted microwave absorption and emission. The distribution-function mechanism arises from microwave-induced changes in the electron distribution. However, the replacement of a smooth random potential by the unidirectional one, leads to different relative strengths of the two contributions to the photoconductivity. The distribution function mechanism dominates the photoconductivity in the direction of the static potential modulation, while both mechanisms contribute equally strongly to the photoconductivity in the perpendicular direction. The unidirectionality of the static potential simplifies greatly the evaluation of the photoconductivities, which follow directly from Fermis golden rule.
We present a systematic study of the microwave-induced oscillations in the magnetoresistance of a 2D electron gas for mixed disorder including both short-range and long-range components. The obtained photoconductivity tensor contains contributions of
The polarization dependence of the low field microwave photoconductivity and absorption of a two-dimensional electron system has been investigated in a quasi-optical setup in which linear and any circular polarization can be produced in-situ. The mic
We present an experimental study on microwave illuminated high mobility MgZnO/ZnO based two-dimensional electron systems with different electron densities and, hence, varying Coulomb interaction strength. The photoresponse of the low-temperature dc r
Rectification of microwave radiation (20-40 GHz) by a line boundary between two two-dimensional metals on a silicon surface was observed and investigated at different temperatures, in-plane magnetic fields and microwave powers. The rectified voltage
We observe a new type of magneto-oscillations in the photovoltage and the longitudinal resistance of a two-dimensional electron system. The oscillations are induced by microwave irradiation and are periodic in magnetic field. The period is determined