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1. 1. Multipoles in Correlated Electron Materials

   Författare :Francesco Cricchio; Lars Nordström; Peter Oppeneer; Igor Solovyev; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; correlated electrons; magnetic ordering; multipoles; actinides; hidden order; high temperature superconductors; Fe pnictides; electronic structure calculations; Condensed matter physics; Kondenserade materiens fysik; Superconductivity; Supraledning; Electronic structure; Elektronstruktur; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : Electronic structure calculations constitute a valuable tool to predict the properties of materials. In this study we propose an efficient scheme to study correlated electron systems with essentially only one free parameter, the screening length of the Coulomb potential. LÄS MER

3. 2. Optical Studies and Applications of Single Quantum Dots

   Författare :Valéry Zwiller; Fasta tillståndets fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; time resolved photoluminescence; Physics; Fysik; Semiconductory physics; Halvledarfysik; Condensed matter:electronic structure; electrical; magnetic and optical properties; supraconductors; magnetic resonance; relaxation; spectroscopy; Kondenserade materiens egenskaper:elektronstruktur; egenskaper elektriska; magnetiska och optiska ; supraledare; spektroskopi; magnetisk resonans; microphotoluminescence; microcavities; photoluminescence; quantum optics; nano-optics; photonics; low dimensional structures; quantum dots; Fysicumarkivet A:2001:Zwiller;

   Sammanfattning : The luminescence from single quantum dots has been studied. Single dot photoluminescence was studied under continuous as well as under pulsed excitation. Time-resolved studies revealed fast relaxations in quantum dots. The time resolved measurements were fitted with a set of rate equations. LÄS MER

4. 3. On the role of the electron-electron interaction in two-dimensional quantum dots and rings

   Författare :Erik Waltersson; Eva Lindroth; Stephanie Reimann; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum dot; quantum ring; quantum dot molecule; electronic structure; two-dimensional; many-body physics; many-body perturbation theory; coupled cluster; coupled cluster singles and doubles; quantum logical gates; quantum computing; quantum control; quantum control algorithm; Electronic structure; Elektronstruktur; fysik; Physics;

   Sammanfattning : Many-Body Perturbation Theory is put to test as a method for reliable calculations of the electron-electron interaction in two-dimensional quantum dots. We show that second order correlation gives qualitative agreement with experiments on a level which was not found within the Hartree-Fock description. LÄS MER

5. 4. First Principles Calculations of Electron Transport and Structural Damage by Intense Irradiation

   Författare :Carlos Ortiz; Olle Eriksson; Mattias Klintenberg; Richard A. London; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Condense matter theory; electronic structure; quasiparticles; GW theory; molecular dynamics; Boltzmann transport; electron transport; impact ionization; structural damage; dielectric response; structural biology; radiation detectors; scintillators; positron emission tommography; Electronic structure; Elektronstruktur; Semiconductor physics; Halvledarfysik; Biological physics; Biologisk fysik; Critical phenomena phase transitions ; Kritiska fenomen fasövergångar ; Functional materials; Funktionella material; Materiefysik; Physics of Matter;

   Sammanfattning : First principle electronic structure theory is used to describe the effect of crystal binding on radiation detectors, electron transport properties, and structural damage induced by intense irradiation. A large database containing general electronic structure results to which data mining algorithms can be applied in the search for new functional materials, a case study is presented for scintillator detector materials. LÄS MER

7. 5. Calculations of Clean and Adsorbate Covered Metal Surfaces and their Core-Level Photoemission Spectra

   Författare :Martin Birgersson; Matematisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; chemical shifts; density functional theory; Condensed matter:electronic structure; electrical; magnetic and optical properties; supraconductors; magnetic resonance; relaxation; Atomic and molecular physics; spektroskopi; magnetisk resonans; supraledare; magnetiska och optiska ; egenskaper elektriska; spectroscopy; Kondenserade materiens egenskaper:elektronstruktur; core-level photoemission; single crystal surfaces; Atom- och molekylärfysik; Fysicumarkivet A:2002:Birgersson; core-hole degeneracies; metal surfaces; adsorption; molecular vibrations;

   Sammanfattning : The present thesis is concerned with the theoretical study of x-ray photoemission spectra from clean and adsorbate-covered metal surfaces. The main tool is ab initio density functional (DFT) total energy calculations. LÄS MER