Electronic structure and energies of alkaline earth oxides: MgO, CaO and SrO

We have used the TB-LMTO scheme to study the electronic structure and the total energies of ceramic oxides MgO, CaO and SrO. All three of them have stable rocksalt structures. We find that although the local density approximation seems to work well for the first two, as the atomic number increases, the approximation begins to fail for SrO. Our calculations tend to show that the last is a metal, whereas experimentally it is as good an insulator as the other two. We suggest that for the larger Z oxides one has to bring in more accurate many-body techniques like the self-interaction correction to get the band gap correctly. (author). 4 refs, 2 figs, 3 tabs