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

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Abstract
In ∼2-μm-wide Hall bars of high-mobility GaAs/AlGaAs heterostructure resistance fluctuations of quasiperiod ΔB≃0.016 T are observed near the diagonal resistance minima for Landau-level filling factors ν=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 ν=(1/3 minimum of the fractional quantum Hall effect we observe similar fluctuation structure, but with a period of ∼0.05 T≃3ΔB, indicative of transport by quasiparticles of fractional charge e/3.