Low-frequency enhancement of the breakdown hysteresis and of the electron localization in quantum Hall systems

In direct measurements of the current-voltage curve hysteresis at different frequencies, we demonstrated that a dramatic increase of breakdown hysteresis happens at low (hertz region) frequencies. For the explanation of the observed dynamical enhancement of breakdown hysteresis, we used an electron heating model and the assumption of a decreasing variable range hopping component of conductivity (possibly due to a shrinking of the localization length) with increasing frequency. Our results showed that the earlier conclusion about a dominance of transitions to the extended states in the quantum Hall effect breakdown is only applicable with respect to the lower limit of the breakdown hysteresis.