Diagonal Conductivity Due To Tunneling In Quantum Hall Systems In The High Electron-Temperature Regime

The diagonal conductivity of two-dimensional electron systems in strong magnetic fields is derived in an analytical form by considering tunneling processes through a saddle point of the slowly-fluctuating potential in the high electron-temperature regime where the breakdown of the integer quantum Hall effect occurs. The calculation is made for a two-dimensional periodic potential modulation with a fixed amplitude equal to the Landau level separation. The electron-temperature dependence of the conductivity is mainly determined by the presence of an activation energy. It is found that an estimated value of the conductivity in the present model at even-integer filling factors is smaller by an order of magnitude than the experimental value in the integer quantum Hall effect breakdown regime.