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 temperatures (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 introducing two factors, the NMR is expressed by a universal function which is determined by the concentration of Si atoms. The behaviour of the two parameters is studied as a function of the Si concentrations, lattice and electron temperature. The results suggest that the NMR is attributed to the reduction of the backscattering in the boundary of the narrow channel which is formed by the random distribution of Si atoms.