Sökning: "electron-electron interaction"
Visar resultat 6 - 10 av 29 avhandlingar innehållade orden electron-electron interaction.
6. Studies of Self-interaction Corrections in Density Functional Theory
Sammanfattning : The self-interaction error (SIE) in density functional theory (DFT) appears from the fact that the residual self-interaction in the Coulomb part and that in the exchange part do not cancel each other exactly. This error is responsible for the unphysical orbital energies of DFT and the failure to reproduce the potential energy curves of several physical processes. LÄS MER
7. Electron transport, interaction and spin in graphene and graphene nanoribbons
Sammanfattning : Since the isolation of graphene in 2004, this novel material has become the major object of modern condensed matter physics. Despite of enormous research activity in this field, there are still a number of fundamental phenomena that remain unexplained and challenge researchers for further investigations. LÄS MER
8. Interactions on the edge of a quantum spin Hall insulator
Sammanfattning : Effects from electron-electron interactions on the edge of a quantum spin Hall insulator are studied using bosonisation and renormalisation group methods. First, a quantum spin Hall device with a point contact connecting two of its edges is considered. LÄS MER
9. Theoretical Developments for the Real-Time Description and Control of Nanoscale Systems
Sammanfattning : In this thesis we focus on improvements of the description of the electron-electron correlation effects in nonequilibrium nanosystems. We mainly focus on developments of two nonequilibrium methods, namely the formalism of Nonequilibrium Green’s Function and Time Dependent Density Functional Theory and we explore the possibility to improve existing approximations in these theories. LÄS MER
10. Unifying first-principles and model approaches for strongly correlated materials : Interplay between long- and short-range correlations
Sammanfattning : In materials with open 3$d$ and 4$f$ shells the valence electrons are relatively localized around the atoms which leads to large electron-electron correlations. These, so called strongly correlated materials, exhibit many intriguing properties such as high $T_c$ superconductivity, colossal magneto-resistance and heavy fermion behaviour. LÄS MER
