Anomalously low magnetoroton energies of the unconventional fractional quantum Hall states of composite fermions

TL;DR

This paper investigates the collective excitations of unconventional fractional quantum Hall states of composite fermions, revealing anomalously low-energy magnetorotons linked to their unique topological properties.

Contribution

It demonstrates the formation of primary magnetorotons with unusually low energies in certain FQHE states, highlighting their distinct topological nature and decay behavior.

Findings

Low-energy magnetorotons observed at specific filling factors

Slow decay of pair-correlation oscillations causes low energies

Distinct topology influences collective mode energies

Abstract

We show a generic formation of the primary magnetorotons in the collective modes of the observed "unconventional" fractional quantum Hall effect (FQHE) states of the composite fermions at the filling factors 4/11, 4/13, 5/13, 5/17, and 3/8 at very low wavevectors with {\em anomalously} low energies which do not have any analogue to the conventional fractional quantum Hall states. Rather slow decay of the oscillations of the pair-correlation functions in these states are responsible for the low-energy magnetorotons. This is a manifestation of the distinct topology predicted before for these FQHE states. Experimental consequences of our theory are also discussed.