Temperature derivative of the chemical potential and its magnetooscillations in two-dimensional system
We report the first thermodynamic measurements of the temperature derivative of chemical potential (∂μ/∂T) in two-dimensional (2D) electron systems. In order to test the technique, we have chosen Schottky gated GaAs/AlGaAs heterojunctions and detected experimentally in this 2D system quantum magneto-oscillations of ∂μ/∂T. We also present a Lifshits-Kosevitch type theory for the ∂μ/∂T magneto-oscillations in 2D systems and compare the theory with experimental data. The magnetic field dependence of the ∂μ/∂T value appears to be sensitive to the density of states shape of Landau levels. The data in low magnetic field domain demonstrate brilliant agreement with theory for non-interacting Fermi gas with Lorentzian Landau level shape.