Current Breakdown of the Fractional Quantum Hall Effect through Contactless Detection of Induced Currents

Abstract

We have observed induced currents associated with the fractional quantum Hall effect (FQHE) in a contactless two-dimensional electron gas subjected to a sweeping magnetic field. Their current-voltage characteristics exhibit pronounced nonlinearities caused by the breakdown of the FQHE at high currents. Our results support the inter-Landau-level-scattering model of breakdown and provide a new local probe of the FQHE energy gaps at $\ensuremath{\nu}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1/3$ and $2/3$. They are also consistent with the composite-fermion picture but yield an effective mass significantly smaller than previously reported values.