The effect of oscillating Fermi energy on the line shape of the Shubnikov-de Haas oscillation in a two dimensional electron gas

TL;DR

This study investigates how oscillating Fermi energy influences the line shape of Shubnikov-de Haas oscillations in a 2D electron gas, revealing that a sinusoidal density of states and Gaussian broadening better explain experimental data.

Contribution

It demonstrates that the oscillating Fermi energy causes specific line shape features in SdH oscillations, with a sinusoidal density of states and Gaussian Landau level broadening providing accurate modeling.

Findings

Line shape is well reproduced by sinusoidal density of states.

Gaussian broadening better describes Landau level disorder effects.

Oscillating Fermi energy impacts the Fourier components of SdH oscillations.

Abstract

The line shape of the Shubnikov-de Haas (SdH) oscillation has been analyzed in detail for a GaAs/AlGaAs two-dimensional electron gas. The line shape, or equivalently the behavior of the Fourier components, of the experimentally observed SdH oscillation is well reproduced by the sinusoidal density of states at the Fermi energy that oscillates with a magnetic field in a saw-tooth shape to keep the electron density constant. This suggests that the broadening of each Landau level by disorder is better described by a Gaussian than by a Lorentzian.