A model for the electronic structure of W impurities was presented which explained recent photoluminescence results. The model was based upon the Ludwig-Woodbury model for interstitial transition-metal impurities in Si, and included a Jahn-Teller coupling which almost entirely quenched the orbital angular momentum. This model permitted a number of predictions to be made. Thus, one result of the strong Jahn-Teller coupling was that the application of a uniaxial stress to monocrystalline samples would lead to very definite splitting of the lines when stresses were applied along [100]; but essentially no splitting for stresses along [111]. Another prediction was that the isotropic g-value in the ground state would be approximately equal to 3, as a result of the almost entirely quenched orbital angular momentum. This contrasted with the value of 3.5 which was predicted by simple crystal-field theory without coupling. Finally, the model predicted an additional peak with an energy of about 1.8eV.

F.G.Anderson, T.Dallas, S.Lal, S.Gangopadhyay, M.Holtz: Solid State Communications, 1997, 102[12], 867-70