QUASI-PARITY-CONSERVING OCTAHEDRAL MODEL FOR (H,BE) AND (D,BE) TUNNELING COMPLEXES IN SILICON

A six-site (octahedral) tunneling model is presented for the (H,Be) and (D,Be) acceptor complexes in silicon. Parity has been found to be, in the approximation used to describe these systems, a conserved quantity. With parity conservation, the model yields spectra that fit the available experimental data with accuracy similar to the previously proposed four-site (tetrahedral) model, but which do not exhibit the unexplained discrepancies - present in the tetrahedral model - between the tunneling frequencies of the complexes and the rotational frequencies of the corresponding diatomic molecules.