Nonconventional odd denominator fractional quantum Hall states in the second Landau level

TL;DR

This paper reports the discovery of a new fractional quantum Hall state at filling factor 2+6/13 in the second Landau level, highlighting deviations from the composite fermion model and suggesting an exotic origin for some states.

Contribution

The paper presents the observation of a new fractional quantum Hall state at 2+6/13 and analyzes its properties, challenging existing models and indicating exotic physics.

Findings

Observation of a new fractional quantum Hall state at 2+6/13

Discrepancy with composite fermion model for certain states

Evidence suggesting some states have an exotic origin

Abstract

We report the observation of a new fractional quantum Hall state in the second Landau level of a two-dimensional electron gas at the Landau level filling factor $\nu=2+6/13$. We find that the model of noninteracting composite fermions can explain the magnitude of gaps of the prominent 2+1/3 and 2+2/3 states. The same model fails, however, to account for the gaps of the 2+2/5 and the newly observed 2+6/13 states suggesting that these two states are of exotic origin.omposite fermion model. However, the weaker 2+2/5 and 2+6/13 states deviate significantly suggesting that these states are of exotic origin.