Browsing by Subject "Atomic particle"

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    Electronic structure of Te-and As-covered Si(211)
    (American Physical Society, 2003) Sen, P.; Batra, I. P.; Sivananthan, S.; Grein, C. H.; Dhar, N.; Çıracı, Salim
    Electronic and atomic structures of the clean and As- and Te-covered Si(211) surface are studied using pseudopotential density-functional method. The clean surface is found to have (2 x 1) and rebonded (1 x 1) reconstructions as stable surface structures, but no π-bonded chain reconstruction. Binding energies of As and Te adatoms at a number of symmetry sites on the ideal and (2 x 1) reconstructed surfaces have been calculated because of their importance in the epitaxial growth of CdTe and other materials on the Si(211) surface. The special symmetry sites on these surfaces having the highest binding energies for isolated As and Te adatoms are identified. But more significantly, several sites are found to be nearly degenerate in binding-energy values. This has important consequences for epitaxial growth processes. Optimal structures calculated for 0.5 monolayer of As and Te coverage reveal that the As adatoms dimerize on the surface while the Te adatoms do not. However, both As- and Te-covered surfaces are found to be metallic in nature.
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    ItemOpen Access
    Spin-polarized ballistic transport in a thin superlattice of zinc blende half-metallic compounds
    (The American Physical Society, 2005) Qian, M. C.; Fong, C. Y.; Pickett, W. E.; Pask, J. E.; Yang, L. H.; Dag, S.
    We examine theoretically ballistic conduction in thin layers of zinc blende half metals, considering 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, we show that surface states thwart half metallicity. However, capping the metal-As bilayers restores half metallicity, and ballistic conduction of electrons within ∼0.3 eV of the Fermi level will give nearly 100% spin-polarized transmission in the direction of the superlattice. Recent developments suggest atomic layer epitaxy can be used to produce such thin layers for spintronic applications.