The electronic charge distribution in crystalline silicon: comparison of ab initio theory and experiment

Recent consolidation by Cummings & Hart [Aust. J. Phys. (1988), 41, 423-431] of five measured data sets of high-precision Si structure factors and subsequent analysis by Deutsch [Phys. Lett. A (1991), 153, 368-372] produced information on the charge density of Si with precision that is unmatched by any other system. A detailed comparison with newly performed ab initio electronic structure calculation within the local density formalism (LDF) is presented here. The convergence of the calculation is extended to the limit at which the results reflect the predictions of the underlying LDF, unobscured by computational uncertainties. Excellent agreement (e.g. R = 0.21% which is three to five times better than previous calculations) is found. This allows the effects of high-index structure factors to be assessed (currently beyond the reach of high-precision measurements) on both static and dynamic deformation charge densities.