BREAKDOWN OF THE QUANTUM HALL-EFFECT IN PERIODIC AND APERIODIC ANTIDOT ARRAYS

We have studied the breakdown of the quantum Hall effect in GaAs/AlxGa 1-xAs heterostructures with antidot arrays as a function of the densit y and distribution of antidots. For periodic arrays (lithographic anti dot diameter 100 nm) and periods from 400 to 1000 nm, the breakdown cu rrent is systematically reduced with increasing antidot density and de termined by the peak value of the local current density. In aperiodic arrays, the breakdown current is markedly lower than in periodic array s of the same antidot density due to higher local current densities at the same total current.