Abstract
Experimental and theoretical investigations on the integer quantized Hall effect in gate-defined narrow Hall bars are presented. At low electron mobility the classical (high-temperature) Hall resistance line RH(B) cuts through the center of all Hall plateaus. In contrast, for our high-mobility samples the intersection point, at even filling factors ν=2, 4, ..., is clearly shifted towards larger magnetic fields B. This asymmetry is in good agreement with predictions of the screening theory, i.e. taking Coulomb interaction into account. The observed effect is directly related to the formation of incompressible strips in the Hall bar. The spin-split plateau at ν=1 is found to be almost symmetric regardless of the mobility. We explain this within the so-called effective g-model.