Low-frequency impedance of quantized Hall conductors

摘要

The longitudinal and the Hall impedances have been measured as a function of the frequency in a two-dimensional electron gas at low temperatures. The frequency dependence of the longitudinal impedance can be explained in terms of an equivalent parallel LCR circuit. An effective inductance term arises due to the capacitive coupling between edge states and is shown to scale as 1/v(2) for different fillings factors. In the low-frequency range the relative difference between the ac and de values of the Hall impedance is found to depend quadratically on the frequency and to scale as 1/v(3). These results are shown to be consistent with the existing theoretical model based on the edge-state picture. Finally, the observed symmetry relations when exchanging current contacts or reversing magnetic field are discussed. [References: 23]