Electronic Processes at the Breakdown of the Quantum Hall Effect

Microscopic processes giving the energy gain and loss of a two-dimensional electron system in long-range potential fluctuations are studied theoretically at the breakdown of the quantum Hall effect in the case of even-integer filling factors. The Coulomb scattering within a broadened Landau level is proposed to give the gain, while the phonon scattering to give the loss. The energy balance equation shows that the electron temperature T_e and the diagonal conductivity sigma_{xx} exhibit a bistability above the lower critical electric field E_{c1}. Calculated values of E_{c1} as well as T_e and sigma_{xx} at E_{c1} are in agreement with the observed values in their orders of magnitude.