Band lineup and electric fields in (-Sn)m/(CdTe)n [001] and [110] superlattices

Results of a systematic study of the electronic properties of (-Sn)m/(CdTe)n [001] and [110] superlattices (m,n=2,3) using the full-potential linearized augmented-plane-wave method are presented. For several different structures we found that -Sn is not able to screen the charge piled up at the polar interface and so gives rise to high electric fields. The heat of formation of the unreconstructed [100] interface drops as the period n is increased, but is still considerably higher than other polar unreconstructed and reconstructed interfaces. We find that the band offset is affected by orientation effects only by 0.2 eV and that the lineup for the nonpolar [110] is the average of the two possible unreconstructed [100] interfaces.