The temperature dependence and scaling of the negative magneto-resistance in Si atomic-layer-doped GaAs

The magneto-transport of Si atomic-layer-doped GaAs was studied at various temperatures. The negative magneto-resistance (NMR) observed at cryogenic t emperatures (4.2-40 K) was decreased by increasing the lattice temperature or the electric field applied parallel to the layer. It is found that, by i ntroducing two factors, the NMR is expressed by a universal function which is determined by the concentration of Si atoms. The behaviour of the two pa rameters is studied as a function of the Si concentrations, lattice and ele ctron temperature. The results suggest that the NMR is attributed to the re duction of the backscattering in the boundary of the narrow channel which i s formed by the random distribution of Si atoms.