Resistance fluctuations in narrow AlGaAs/GaAs heterostructures: Direct evidence of fractional charge in the fractional quantum hall effect

Abstract

In \ensuremath{\sim}2-\ensuremath{\mu}m-wide Hall bars of high-mobility GaAs/AlGaAs heterostructure resistance fluctuations of quasiperiod \ensuremath{\Delta}B\ensuremath{\simeq}0.016 T are observed near the diagonal resistance minima for Landau-level filling factors \ensuremath{\nu}=1,2,3,4. This behavior is consistent with resonant reflection through magnetically bound states as a mechanism for the breakdown of dissipationless transport in narrow channels. In the \ensuremath{\nu}=(1/3 minimum of the fractional quantum Hall effect we observe similar fluctuation structure, but with a period of \ensuremath{\sim}0.05 T\ensuremath{\simeq}3\ensuremath{\Delta}B, indicative of transport by quasiparticles of fractional charge e/3.