ABSTRACT
This paper reviews experimental researches of breakdown of the quantum Hall effect in GaAs/AlGaAs heterostructures due to current carried out in Gakushuin University. We used specially designed Hall bars which eliminate influence of dissipation at current electrodes and found following results: (1) Critical current at the onset of the breakdown is proportional to the sample width. (2) The critical Hall electric field at the breakdown for quantized Hall plateau with plateau quantun numbers i = 2 and 4 is proportional to B 3/2 and does not depend on the electron mobility of the sample where B is the magnetic flux density at the plateau center.
