Band Lineups at II-VI Heterojunctions: Failure of the Common-Anion Rule

Band-edge discontinuities are calculated for tellurium-based II-VI heterojunctions. Contrary to the widely accepted common-anion rule, large valence-band discontinuities are found in most cases, including HgTe-CdTe. The common-anion rule is examined and predicted to fail, not only here, but for all lattice-matched II-VI and III-V heterojunctions. An experiment is proposed to test these predictions.