Role of exciton screening in the 7/3 fractional quantum Hall effect

TL;DR

This paper investigates how exciton screening influences the excitations in the 7/3 fractional quantum Hall state, revealing significant renormalization effects due to composite fermion interactions.

Contribution

It demonstrates that exciton screening causes strong renormalization of excitations at 7/3, highlighting the importance of exciton clouds in composite fermion behavior.

Findings

Exciton screening significantly renormalizes 7/3 excitations.

Composite fermions are dressed by large exciton clouds.

Implications for experiments and finite system studies.

Abstract

The excitations of the 7/3 fractional Hall state, one of the most prominent states in the second Landau level, are not understood. We study the effect of screening by composite fermion excitons and find that it causes a strong renormalization at 7/3, thanks to a relatively small exciton gap and a relatively large residual interaction between composite fermions. The excitations of the 7/3 state are to be viewed as composite fermions dressed by a large exciton cloud. Their wide extent has implications for experiments as well as for analysis of finite system exact diagonalization studies.