Extended Hückel theory for band structure , chemistry , and transport .

In this second paper, we develop transferable semiempirical extended Hückel theoretical EHT parameters for the electronic structure of another technologically important material, namely, silicon. The EHT parameters are optimized to experimental target values of the band dispersion of bulk silicon. We quantitatively benchmark our parameters to bulk electronic properties such as band edge energies and locations, effective masses, and spin-orbit coupling parameters, competitive with a nearest-neighbor sp3d5s* orthogonal tight-binding model for silicon of T. Boykin et al. Phys. Rev. B 69, 115201 2004 that has been widely used to model silicon-based devices see, e.g., A. Rahman et al. Jpn. J. Appl. Phys. Part I 44, 2187 2005 and J. Wang et al. Appl. Phys. Lett. 86, 093113 2005 . The transferability of the parameters is checked for multiple physical and chemical configurations, specifically, two different reconstructed surfaces, Si 100 2 1 and Si 111 2 1 . The robustness of the parameters to different environments is demonstrated by comparing the surface band structures with density functional theory GW calculations and photoemission/inverse photoemission experiments. We further apply the approach to calculate the one-dimensional band dispersion of an unrelaxed rectangular silicon nanowire and explore the chemistry of surface passivation by hydrogen. Our EHT parameters thus provide a quantitative model of bulk silicon and silicon-based interfaces such as contacts and reconstructed surfaces, which are essential ingredients towards a quantitative quantum transport simulation through silicon-based heterostructures. © 2006 American Institute of Physics. DOI: 10.1063/1.2259820