Microscopic modelling of perpendicular electronic transport in doped   multiple quantum wells
  We present a microscopic calculation of transport in strongly doped superlattices where domain formation is likely to occur. Our theoretical method is based on a current formula involving the spectral functions of the system, and thus allows, in principle, a systematic investigation of various interaction mechanisms. Taking into account impurity scattering and optical phonons we obtain a good quantitative agreement with existing experimental data from Helgesen and Finstad (J. Appl. Phys. 69, 2689, (1991)). Furthermore the calculated spectral functions indicate a significant increase of the average intersubband spacing compared to the bare level differences which might explain the experimental trend. 
Andreas Wacker and Antti-Pekka Jauho (Mikroelektronik Centret,   Danmarks Tekniske Universitet, Lyngby)