Model for breakdown of laminar flow of a quantum Hall fluid around a charged impurity: comparison with experiment

In samples used to maintain the US resistance standard the breakdown of the dissipationless integer quantum Hall effect occurs as a series of dissipative voltage steps. A mechanism for this type of breakdown is proposed, based on the generation of magneto-excitons when the quantum Hall fluid flows past an ionised impurity above a critical velocity. The calculated generation rate gives a voltage step height in good agreement with measurements. We also compare this model to a hydrodynamic description of breakdown.