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Other models

It is possible to construct various other defect structures that act as double donors, involving different numbers of oxygen atoms (Oni, $n \geq 3$). We have also modelled many of these for comparison with the di-y-lid model, and to determine whether they could be responsible for other members of the thermal donor family.

Figure 9.10: The top Kohn-Sham eigenvalues for various alternative thermal donor models, all in the +2 charge state. Black boxes denote filled state, white boxes for empty states. The eigenvalues have been arbitrarily scaled to the experimental band gap of 1.16eV. Structures are 3Oi species (a) Snyder/Stavola, (b) Partially dissociated trimer, 4Oi species (c) `Flanked square' model, (d) Di-square model, (e) 5Oi STD analogue, and (f) 6Oi di-y-lid with dimer in central Si-Si backbonds.
\psfig {file=oxygen/thermal/diags/levels.all.eps,width=12cm}


Chris Ewels