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Density functional theory

Physics Faculty Publications

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Full-Text Articles in Physics

Electronic Structures Of Lanthanum, Samarium, And Gadolinium Sulfides, Lu Wang, Chris M. Marin, Wai-Ning Mei, Chin Li Cheung May 2015

Electronic Structures Of Lanthanum, Samarium, And Gadolinium Sulfides, Lu Wang, Chris M. Marin, Wai-Ning Mei, Chin Li Cheung

Physics Faculty Publications

In this study, we report our efforts to elucidate the electronic structures of two lattice structures of lanthanide sulfides (LnS and Ln3S4) and for three lanthanides (Ln = La, Sm and Gd) using density functional theory calculations performed with the CASTEP code. A DFT+U method was used for the corrections of on-site Coulomb interactions with U = 6 eV. The calculated electronic structures show that both lanthanum and gadolinium sulfides have metallic properties, consistent with the available experimental results. However, the calculated electronic structure of Sm3S4 is considerably different from those of the La3S4 and Gd3S4 and is predicted to …


Atomic Size Mismatch Strain Induced Surface Reconstructions, Jessica E. Bickel, Normand A. Modine, Anton Van Der Ven, Joanna Mirecki Millunchick Feb 2008

Atomic Size Mismatch Strain Induced Surface Reconstructions, Jessica E. Bickel, Normand A. Modine, Anton Van Der Ven, Joanna Mirecki Millunchick

Physics Faculty Publications

The effects of lattice mismatch strain and atomic size mismatch strain on surface reconstructions are analyzed using density functional theory. These calculations demonstrate the importance of an explicit treatment of alloying when calculating the energies of alloyed surface reconstructions. Lattice mismatch strain has little impact on surface dimer ordering for the α2(2×4) reconstruction of GaAs alloyed with In. However, atomic size mismatch strain induces the surface In atoms to preferentially alternate position, which, in turn, induces an alternating configuration of the surface anion dimers. These results agree well with experimental data for α2(2×4) domains in InGaAs∕GaAs surfaces.


Domain-Wall Magnetoresistance Of Co Nanowires, Renat F. Sabirianov, Ashok K. Solanki, J. D. Burton, Sitaram S. Jaswal, Evgeny Y. Tsymbal Aug 2005

Domain-Wall Magnetoresistance Of Co Nanowires, Renat F. Sabirianov, Ashok K. Solanki, J. D. Burton, Sitaram S. Jaswal, Evgeny Y. Tsymbal

Physics Faculty Publications

Using density functional theory implemented within a tight-binding linear muffin-tin orbital method we perform calculations of electronic, magnetic, and transport properties of ferromagnetic free-standing fcc Co wires with diameters up to 1.5 nm. We show that finite-size effects play an important role in these nanowires resulting in oscillatory behavior of electronic charge and the magnetization as a function of the wire thickness, and a nonmonotonic behavior of spin-dependent quantized conductance. We calculate the magnetoresistance (MR) of a domain wall (DW) modeled by a spin-spiral region of finite width sandwiched between two semi-infinite Co wire leads. We find that the DW …