Subband mobility of quasi-two-dimensional electrons in Si atomic layer doped GaAs

Subband mobility and conductivity of quasi-two-dimensional electrons in Si atomic layer doped GaAs are estimated for the first time. The oscillations for different subbands in low-temperature magnetoresistance are separated from each other by using the reverse Fourier transform technique. The mobility for each subband is then determined by fitting the field dependence of the amplitudes with conventional theory. A large subband mobility difference up to 20:1 is found. This is mainly due to strong screening. Furthermore, a partial conductivity for each subband is calculated and the importance of the shallower subbands in total current transport is clarified.