Abstract
The photovoltaic effect induced by terahertz radiation in a gatedtwo-dimensional electron gas in magnetic field is considered theoretically. Itis assumed that the incoming radiation creates an ac voltage between the sourceand gate and that the gate length is long compared to the damping length ofplasma waves. In the presence of pronounced Shubnikov-de Haas oscillations, animportant source of non-linearity is the oscillating dependence of the mobilityon the ac gate voltage. This results in a photoresponse oscillating as afunction of magnetic field, which is enhanced in the vicinity of the cyclotronresonance, in accordance with recent experiments. Another, smooth component ofthe photovoltage, unrelated to SdH oscillations, has a maximum at cyclotronresonance.