Transferable nonorthogonal tight-binding parameters for silicon

Nonorthogonal Slater-Koster (``tight-binding'') parameters have been fitted to linear muffin-tin orbital band structures of silicon in the hypothetical sc, fcc, and bcc structures at the density of ordinary diamond-cubic silicon. First- and second-neighbor parameters are used for all three structures. When the eight parameters (H_ssσ,...,S_ppπ) are plotted as a function of neighbor distance, they describe approximate smooth curves which align well with the values found by Mattheiss and Patel for diamond-cubic Si, even though local coordination is entirely different. This suggests an approximate transferability of tight-binding parameters, at least if the volume is constant and coordination number is four or higher.