ELECTRONIC-STRUCTURE OF THE SI6 GE6(111) SUPERLATTICE STRAINED TO A GE SUBSTRATE/

Using the total energy pseudopotential method we have calculated the e lectronic structure of a Si6/Ge6(111) superlattice, strained to a Ge s ubstrate. We have also calculated the electronic structure of Si and G e, both unstrained and strained, in the 12-atom hexagonal unit cell of the superlattice and we demonstrate how the lowest lying conduction b and states at the face-centred cubic GAMMA, X and L-points are depende nt on strain, fold in and mix to form the superlattice states. The opt ical transition matrix elements of the direct transitions are consider ed and the valence band offset of this heterojunction is calculated.