Response of incompressible fractional quantum Hall states to magnetic and non-magnetic impurities

TL;DR

This study uses exact diagonalization to analyze how various fractional quantum Hall states respond to local impurities, revealing differences in inertness and spin correlations, and comparing magnetic and non-magnetic impurity effects.

Contribution

It provides new insights into the impurity response of fractional quantum Hall states, highlighting the inertness of the 2/3 singlet state and its interpretation as a paired electron liquid.

Findings

2/3 singlet state is more inert than polarized state

The 2/3 singlet state behaves as a liquid of electron pairs with opposite spins

Different responses to magnetic and non-magnetic impurities are characterized

Abstract

Using exact diagonalization we examine the response of several most prominent fractional quantum Hall states to a single local impurity. The 2/3 singlet state is found to be more inert than the polarized one in spite of its smaller incompressibility gap. Based on its spin-spin correlation functions we interpret it as a liquid of electron pairs with opposite spin. A comparison of different types of impurities, non-magnetic and magnetic, is presented.