Intersubband-coupling and screening effects on the electron transport in a quasi-two-dimensional δ-doped semiconductor system

The effects due to intersubband coupling and screening on the ionized impurity scattering are studied for a quasi-two-dimensional electron system in δ-doped semiconductors. We found that intersubband coupling plays an essential role in describing the screening properties and the effect of ionized impurity scattering on the mobility in a multisubband system. At the onset of the occupation of a higher subband, the screening due to the intersubband coupling leads to a reduction of the small angle scattering rate in the lower subband. We showed that such an effect is significant in a δ-doped quantum well and results in a pronounced increase of the quantum mobility at the onset of the occupation of a higher subband.