Pulsed Magnetic Field Measurements of the Composite Fermion Effective Mass

TL;DR

This study measures the effective mass of composite fermions in high magnetic fields, revealing a linear increase with effective field and unifying data across fractions, with implications for understanding quantum Hall states.

Contribution

It provides new high-field magnetotransport data showing the linear dependence of composite fermion effective mass on effective magnetic field, extending previous lower-field results.

Findings

Effective mass reaches 1.6m_e at B* of 14 T

Data unified by effective field B* across samples

Energy gap increases with sqrt(B*) at high fields

Abstract

Magnetotransport measurements of Composite Fermions (CF) are reported in 50 T pulsed magnetic fields. The CF effective mass is found to increase approximately linearly with the effective field $B^*$, in agreement with our earlier work at lower fields. For a $B^*$ of 14 T it reaches $1.6m_e$, over 20 times the band edge electron mass. Data from all fractions are unified by the single parameter $B^*$ for all the samples studied over a wide range of electron densities. The energy gap is found to increase like $\sqrt{B^*}$ at high fields.