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Visar resultat 1 - 5 av 330 avhandlingar som matchar ovanstående sökkriterier.

1. 1. 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

3. 2. 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

4. 3. 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

5. 4. Photoelectron Spectroscopy on Atoms, Molecules and Clusters : The Geometric and Electronic Structure Studied by Synchrotron Radiation and Lasers

   Författare :Torbjörn Rander; Olle Björneholm; Gunnar Öhrwall; Maxim Tchaplyguine; Matthias Neeb; Uppsala universitet; []
   Nyckelord :Atomic and molecular physics; Free clusters; Electron spectroscopy; Doped clusters; Laser excitation; Alkali metals; Electronic structure; Geometric structure; X-ray photoelectron spectroscopy XPS ; Resonant Auger spectroscopy RAS ; Near-threshold x-ray absorption fine structure NEXAFS ; Ultraviolet photoelectron spectroscopy UPS ; Detuning; Ultra-fast dissociation UFD ; Sodium; Potassium; Oxygen; Bromomethane; Argon; Xenon; Krypton; Molecular field splitting; Core hole lifetime; Core excitation; Atom- och molekylfysik;

   Sammanfattning : Atoms, molecules and clusters all constitute building blocks of macroscopic matter. Therefore, understanding the electronic and geometrical properties of such systems is the key to understanding the properties of solid state objects. LÄS MER

7. 5. Physics of Strong Correlations in Electronic Structure and Model Calculations

   Författare :Urban Lundin; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Strongly correlated electrons; Electronic structure calculations; Fysik; Physics; Fysik; fysik; Physics;

   Sammanfattning : Using field theoretical methods models of strongly correlated electrons have been investigated. Application to electronic structure calculations has been made. LÄS MER