Temperature dependence of the compressibility of two-dimensional electron systems with long-range potential fluctuations in the quantum Hall effect regime

Abstract

The temperature dependence of the compressibility of two-dimensional electron systems (2DESs) in GaAs/AlGaAs heterostructures in the quantum Hall effect regime have been studied both experimentally and theoretically. The compressibility was determined using the capacitance spectroscopy technique and the measurements of a low-frequency electric field penetrating through the 2DES. The measured temperature dependences of the 2DES compressibility are quantitatively described using a model taking into account inhomogeneity of the electron density at a finite temperature. Changes in the chemical potential of the 2DES in the vicinity of even filling factors determined from the capacitive and transport measurements are mutually consistent and agree with the results of finite-temperature calculations.