Sökning: "structure calculations"

Visar resultat 1 - 5 av 817 avhandlingar innehållade orden structure calculations.

1. 1. Formation stability and electronic structure of surfaces and interfaces from first principles

   Författare :Jochen Rohrer; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; band structure; van der Waals interaction; electronic structure; graphane; graphene; atomic structure; growth; thin film; interface; density functional theory; CVD; Alumina; nucleation;

   Sammanfattning : This thesis deals with two closely interwoven aspects of first-principle(density functional theory) materials modeling:(1)~prediction of atomic structure & chemical composition,and (2)~prediction of electronic properties.In the first part, we focus on atomic structure (AS) and chemical composition (CC) of surface and interface systems. LÄS MER

3. 2. Parallelization of dynamic algorithms for electronic structure calculations

   Författare :Anton G. Artemov; Emanuel H. Rubensson; Maya Neytcheva; Bo Kågström; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; parallelization; task-based programming; matrix algorithms; sparse matrices; inverse factorization; localized computations; density matrix methods; electronic structure calculations; Scientific Computing; Beräkningsvetenskap;

   Sammanfattning : The aim of electronic structure calculations is to simulate behavior of complex materials by resolving interactions between electrons and nuclei in atoms at the level of quantum mechanics. Progress in the field allows to reduce the computational complexity of the solution methods to linear so that the computational time scales proportionally to the size of the physical system. LÄS MER

4. 3. Electronic Structure Calculations of Point Defects in Semiconductors

   Författare :Andreas Höglund; Susanne Mirbt; Alison Mainwood; Uppsala universitet; []
   Nyckelord :Physics; electronic structure calculations; point defects; semiconductor; formation energy; equilibrium solubility limit; thermodynamic equilibrium concentration; transfer levels; negative-U; 110 surface; diffusion; activation energy; solar cells; Fysik;

   Sammanfattning : In this thesis point defects in semiconductors are studied by electronic structure calculations. Results are presented for the stability and equilibrium concentrations of native defects in GaP, InP, InAs, and InSb, for the entire range of doping conditions and stoichiometry. LÄS MER

5. 4. Magnetism and Structure in Metallic Multilayers

   Författare :Erik Holmström; Turek Ilja; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Magnetism; Interfaces; Structure; KKR-ASA; CPA; Quantum Well; Fysik; Physics; Fysik;

   Sammanfattning : The interplay between magnetism and structure has been studied in magnetic multilayers by electronic structure calculations based on density functional theory and analyzed in terms of models. The main ideas behind the Korringa-Kohn-Rostocker Green’s function method are described and the implementation of the coherent potential approximation is outlined. LÄS MER

7. 5. Electronic Structure Calculations: Materials with Weak and Strong Correlations

   Författare :Krister Karlsson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; photoemission spectroscopy; band structure calculations;

   Sammanfattning : This thesis is devoted to studies of various electronic properties which can be extracted from photoemission spectroscopy. Both weakly and strongly correlated systems are discussed, ranging from free electron metal surfaces to strongly correlated copper oxide compounds. LÄS MER