QHE BREAKDOWN INDUCED BY A SINGLE ANTIDOT - COULOMB STAIRCASE IN THE BREAKDOWN CURRENT

We have studied the breakdown of the quantum Hall effect in a constric tion defined by two trench fingers and an antidot, patterned on a Corb ino ring. At filling factors near v = 2, the I-V characteristics show well developed current steps, which we interpret as a Coulomb staircas e phenomenon due to charging of compressible strips around the antidot . The evolution of the current steps with filling factor is explained in terms of quasi-elastic inter Landau level scattering. (C) 1998 Else vier Science B.V. All rights reserved.