Temperature derivative of the chemical potential and its magnetooscillations in two-dimensional system

TL;DR

This study presents the first thermodynamic measurements of the temperature derivative of chemical potential in 2D electron systems, revealing quantum magnetooscillations and confirming theoretical predictions for non-interacting Fermi gases.

Contribution

It introduces a novel measurement technique for dμ/dT in 2D systems and compares experimental results with a Lifshits-Kosevitch type theory.

Findings

Experimental detection of quantum magnetooscillations of dμ/dT.

Agreement between theory and experiment for non-interacting Fermi gas.

Sensitivity of dμ/dT to Landau level density of states shape.

Abstract

We report first thermodynamic measurements of the temperature derivative of chemical potential (d{\mu}/dT) 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 magnetooscillations of d{\mu}/dT. We also present a Lifshits-Kosevitch type theory for the d{\mu}/dT magnetooscillations in 2D systems and compare the theory with experimental data. The magnetic field dependence of the d{\mu}/dT 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.