The integer and fractional quantum Hall states are known to break down at high dc bias, exhibiting deviation from the ideal incompressible behavior. We measure breakdown of the \nu = 2, 3, 4, 5 integer and the \nu = 4/3 and 5/3 fractional states in a quantum point contact (QPC) of lithographic width ~600 nm. Dependence of the critical current on magnetic field, QPC gate voltage, and QPC width are presented. Of particular interest, the critical current of the 4/3 and 5/3 fractional states shows the opposite dependence on QPC width compared to the integer states. This previously unobserved result is not explained by current theories of breakdown.
@article{arxiv.1204.5712,
title = {Breakdown of the integer and fractional quantum Hall states in a quantum point contact},
author = {C. Dillard and X. Lin and M. A. Kastner and L. N. Pfeiffer and K. W. West},
journal= {arXiv preprint arXiv:1204.5712},
year = {2015}
}