Hall magnetocapacitance in two-dimensional electron systems

The magnetocapacitance of a two-dimensional electron system (2DES) is investigated experimentally, both under the and away from quantum Hall conditions, at frequencies between kHz and 100 MHz. The nature of the capacitive signal in a bounded 2DES is determined by a resistive cutoff frequency 1/tau proportional to sigma(xx), the longitudinal magnetoconductivity. A new response mechanism is reported for angular frequencies omega > 1/tau, which is controlled by the transverse or Hall conductivity sigma(xy) and the boundaries of the sample. The mechanism is also found at frequencies far below those of the edge magnetoplasma resonances and away from the quantum Hall regime.