A New Method for Comprehensive Measurements of the Magnetotransport Characteristics and Compressibility of Electrons in Channels of Field-Effect Transistors

We describe a new method developed by us that consists in simultaneous measurements of the magnetoresistivity tensor of a quasi-2D electronic system in the channel of a field-effect transistor (FET) and several magnetocapacitances between the channel and the gates located on its both sides. The results that can be obtained using this method have been showcased in a FET with a channel in the form of a GaAs quantum well (QW) of 60-nm width within the interval of gate voltages, where this system in a weak magnetic field can be considered as a double-layer electronic system. We prove the convenience of this technique when studying the redistribution of electrons between the layers in a magnetic field and for obtaining the most comprehensive information about the properties of electronic layers even in the absence of separate ohmic contacts to each of these layers.