Comment on ``Effective Mass and g-Factor of Four Flux Quanta Composite Fermions"

TL;DR

This paper comments on experimental findings about four flux quanta composite fermions, explaining the observed fractional quantum Hall gap collapse by considering electron-hole symmetry, thus addressing a previously unresolved mystery.

Contribution

It clarifies the role of electron-hole symmetry in explaining the collapse of quantum Hall gaps for four flux quanta composite fermions.

Findings

Collapse of fractional quantum Hall gaps explained by electron-hole symmetry

Part of the experimental mystery is resolved through theoretical insight

Supports the fermionic behavior of $^4$CFs with mass and spin similar to $^2$CFs

Abstract

In a recent Letter, Yeh et al.[Phys. Rev. Lett. 82, 592 (1999)] have shown beautiful experimental results which indicate that the composite fermions with four flux quanta ($^4$CF) behave as fermions with mass and spin just like those with two flux quanta. They observed the collapse of the fractional quantum Hall gaps when the following condition is satisfied with some integer $j$, $g^*\mu_{\rm B}B_{\rm tot} = j \hbar \omega_{\rm c}^*$, where $g^*$ and $\omega_{\rm c}^*$ are the g-factor and the cyclotron frequency of the $^4$CF, respectively. However, in their picture the gap at the Fermi energy remains always finite even if the above condition is satisfied, thus the reason of the collapse was left as a mystery. In this comment it is shown that part of the mystery is resolved by considering the electron-hole symmetry properly.