ELECTRICAL-CONDUCTIVITY OF DELTA-DOPING SUPERLATTICES PARALLEL TO THEGROWTH DIRECTION

The electrical conductivity sigma has been calculated for n-type delta doping GaAs superlattices (SLs) in a direction perpendicular to the l ayers. The transport along the SL growth direction is investigated by first performing self-consistent calculations of the miniband structur e as a function of the SLs' periods d and the sheet doping concentrati ons N-D. The Schrodinger equation, with the appropriate periodic bound ary condition, coupled to the Poisson equation are self-consistently s olved within the framework of the local density functional approximati on for the electron exchange-correlation effects. Assuming that the tr ansport in the SL occurs through extended miniband states, sigma is ca lculated at zero temperature and low field ohmic limits by the quasi-c lassical Boltzmann kinetic equation. Using semiquantitative arguments we have shown recently that the particular miniband structure of the d elta doping SLs leads to a plateau-like behaviour of sigma as a functi on of the Fermi level position or of the donor concentration. In the p resent work numerical values of sigma are presented.