Abstract
The spin susceptibility of Si:P is calculated for concentrations of donors at which the extrinsic electrons form a metallic band. The calculations are based on the Brinkman-Rice expression for the susceptibility of a highly correlated tight-binding system, and the hopping integral T and the intra-, atomic repulsion U are evaluated from realistic impurity wave functions. The calculated susceptibility shows a strong enhancement due to electron correlation effects, and is in qualitative agreement with recent ESR experiments. Estimates of the Curie-Weiss temperature of the non-metallic phase and of the critical concentration for the metal-non-metal transition are also presented. Finally, the present model is compared with other models.