Scaling Behaviour of Doped AlGaAs/GaAs Heterostructures in the Quantum Hall Regime
The influence of repulsive (Be) and attractive (Si) scattering centers close to the two dimensional electron gas of AlGaAs/GaAs heterostructures on characteristic transport properties has been studied. The temperature dependent halfwidth of the Shubnikov-de Haas-peaks ΔB (T) and the maximum of the slope of the Hall resistance δρxy /δB (T) between adjacent Hall plateaus have been investigated in the temperature range from 1.1K down to 40 mK. We have studied both delta-doped and homogeneously doped samples. In contrast to results reported for InGaAs/InP-heterostructures where a scaling exponent ϰ= 0.42± 0.04 with ΔB ∝ Tϰ and (δρxy /δB)max ∝ T−ϰ is found our data lead to scaling exponents which depend on the distribution and the density of the impurities. The values for ϰ are in the range of 0.36 to 0.81.
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