[en] We develop expressions for the electrostatic potential and total energy of crystalline solids which are amenable to direct evaluation in real space. Unlike conventional reciprocal space formulations, no Fourier transforms or reciprocal lattice summations are required, and the formulation is well suited for large-scale, parallel computations. The need for reciprocal space expressions is eliminated by replacing long-range potentials by equivalent localized charge distributions and incorporating long-range interactions into boundary conditions on the unit cell. In so doing, a simplification of the conventional reciprocal space formalism is obtained. The equivalence of the real- and reciprocal space formalisms is demonstrated by direct comparison in self-consistent density-functional calculations

[en] Separate abstracts were prepared for each of the 53 included papers. Abstracts for the remaining papers appeared previously in ERA

[en] High-Z metals constitute a particular challenge for large-scale ab initio calculations, as they require high resolution due to the presence of strongly localized states and require many eigenstates to be computed due to the large number of electrons and need to accurately resolve the Fermi surface. Here, we report recent findings on high-Z materials, using an efficient massively parallel planewave implementation on some of the largest computational architectures currently available. We discuss the particular architectures employed and methodological advances required to harness them effectively. We present a pair-correlation function for U, calculated using quantum molecular dynamics, and discuss relaxations of Pu atoms in the vicinity of defects in aged and alloyed Pu. We find that the self-irradiation associated with aging has a negligible effect on the compressibility of Pu relative to other factors such as alloying

[en] Two Si-based spintronic materials, a Mn-Si digital ferromagnetic heterostructure ((delta)-layer of Mn doped in Si) with defects and dilutely doped Mn_xSi_1-x alloy are investigated using a density-functional based approach. We model the heterostructure and alloy with a supercell of 64 atoms and examine several configurations of the Mn atoms. We find that 25% substitutional defects without vacancies in the (delta) layer diminishes half metallicity of the DFH substantially. For the alloy, the magnetic moment M ranges from 1.0-9.0 μ_B/unit-cell depending on impurity configuration and concentration. Mn impurities introduce a narrow band of localized states near E_F. These alloys are not half metals though their moments are integer. We explain the substantially different magnetic moments

[en] A brief comparison of conventional electronics and spintronics is given. The key features of half metallic binary compounds with the zincblende structure are presented, using MnAs as an example. We discuss the interactions responsible for the half metallic properties. Special properties of superlattices and a digital ferromagnetic heterostructure incorporating zincblende half metals are also discussed

[en] The authors examine theoretically conduction processes near the Fermi energy of thin layers of zincblende structure half metals, using as an example a superlattice consisting of monolayers of GaAs and MnAs, a bilayer of CrAs, and a bilayer of GaAs. By artificially separating bilayers, they show that non-fourfold coordinated Cr states thwart half metallicity. However, capping the metal-As bilayers restores half metallicity and ballistic conduction of electrons around 0.3 eV above the Fermi level will give nearly 100% spin-polarized transmission in the direction of the thin superlattice. Recent developments suggest atomic layer epitaxy can be used to produce such thin layers for spintronics applications