Gated two-dimensional electron gas in magnetic field: Nonlinear versus linear regime

We study the effect of magnetic field on the properties of a high-mobility gated two-dimensional electron gas in a field-effect transistor with the Hall bar geometry. When approaching the current saturation when the drain side of the channel becomes strongly depleted, we see a number of unusual effects related to the magnetic field induced redistribution of the electron density in the conducting channel. The experimental results obtained in the nonlinear regime have been interpreted based on the results obtained in the linear regime by a simple theoretical model, which describes quite well our observations.