gshift in thermal donors in silicon

The anisotropic g factor in thermal donors is studied. Assuming a two-valley shallow-donor state with a local strain in the [110] direction, from strain experiments by Wilson and Feher, it is argued that an average strain 〈εxy〉 of 0.0029 would account for the observed gxy. An elastic continuum model for the strain due to Eshelby gives a reasonable estimate of the effect, but does not shed much light on the question of the thermal-donor core. The decrease in gxy with annealing is explained by relating it to the decrease in binding energy.