Sökning: "coherent-potential approximation"
Visar resultat 1 - 5 av 30 avhandlingar innehållade orden coherent-potential approximation.
Sammanfattning : The subject of the present thesis is a theoretical investigation of magnetism and its crystal structure dependence by means of electronic-structure calculations from first principles. The theoretical treatment is based on density functional theory and the so called linear muffin-tin orbital method is used in its full-potential version as well as in an atomic sphere approximation. LÄS MER
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
Sammanfattning : This thesis focus on the magnetic behavior, from single atoms to bulk materials. The materials considered in this thesis have been studied by computational methods based on ab initio theory, density functional theory (DFT), including treatment of the spin-orbit coupling, non-collinear magnetism, and methods capable of treating discorded systems. LÄS MER
Sammanfattning : Present-day electronics employ circuits of smaller and smaller dimensions, and today the length scales are so small that the laws of physics which rule micro-cosmos, quantum mechanics, become directly important. This thesis reports on theoretical work on electron transport in different nanostructures. LÄS MER
5. Development and application of Muffin-Tin Orbital based Green’s function techniques to systems with magnetic and chemical disorder
Sammanfattning : Accurate electronic structure calculations are becoming more and more important because of the increasing need for information about systems which are hard to perform experiments on. Databases compiled from theoretical results are also being used more than ever for applications, and the reliability of the theoretical methods are of utmost importance. LÄS MER