Bulk conductivity at quantum Hall plateaux by magnetocapacitance measurement

We have investigated the bulk conductivity (σxx) of two-dimensional electron gas in GaAs/AlGaAs heterostructure in the quantum Hall regime by the magnetocapacitance measurement with Corbino geometry sample. The σxx at the Hall plateau down to 10−11 S is measured, and the temperature dependence of σxx is discussed. The experimental characteristics of the capacitance measurement is also discussed.