The diagonal and off-diagonal AC conductivity of two-dimensional electron gases with contactless Corbino geometry in the quantum Hall regime

We have investigated the AC conductivity elements in the quantum Hall regime of two-dimensional electron gases coupled capacitively to electrodes with Corbino geometry. The samples are GaAlAs/GaAs single heterostructures, and the measurements are made at low frequencies, up to 20 kHz. The diagonal conductivity is derived from magnetocapacitance measurements. It increases with increasing frequency according to a power law at integer filling factors. The exponent of the power law depends on both temperature and filling factor. Ratios between Hall conductivities at different filling factors are obtained by inductive measurements of the circulating current. They are found to agree with quantization in multipla of e2/h at the integer filling factors. ©1996 American Institute of Physics.