Fermi Contour Disintegration of Quasi-2D Electrons in Parallel Magnetic Fields

TL;DR

This study investigates how a parallel magnetic field distorts and disintegrates the Fermi contour of quasi-2D electrons in a GaAs quantum well, combining experimental measurements with semi-classical calculations.

Contribution

It provides the first direct experimental observation of Fermi contour disintegration in quasi-2D electrons under parallel magnetic fields, confirming theoretical predictions.

Findings

Fermi contour disintegration observed experimentally

Good agreement with semi-classical calculations

Evidence of magnetic-breakdown-like behavior

Abstract

In a quasi two-dimensional electron system with non-zero layer thickness, a parallel magnetic field (B||) can couple to the out-of-plane electron motion and lead to a severe distortion and eventual disintegration of the Fermi contour. Here we directly and quantitatively probe this evolution through commensurability and Shubnikov-de Haas measurements on electrons confined to a 40-nm-wide GaAs (001) quantum well. We are able to observe the Fermi contour disintegration phenomenon, in good agreement with the results of semi-classical calculations. Experimentally we also observe intriguing features, suggesting magnetic-breakdown-type behavior when the Fermi contour disintegrates.