Theory of Magnetic Materials - The goal of this project is to investigate the energy levels, wave functions, and derived properties of electrons in solids from two points of view. Density functional theory is the basis for most current calculations of the electronic structure of solids from a single-particle point of view. Development of improved computational techniques is proposed, which are then to be applied to a range of systems of special interest, including transition metals and high-Tc superconductors. The alternate viewpoint concerns systems in which the electron-electron interaction is strong, so that the single- electron picture is inadequate for description of the electronic behavior. This project proposes to find and interpret exact solutions of the many-body problem on finite clusters, and subsequently generalize these result to larger systems. %%% The electronic structure of solids determines virtually all of their physical properties. This proposal seeks to extend our ability to calculate and describe this structure in two ways. The most commonly used technique for determining electronic structure will be improved to allow their application to systems which are currently intractable. Secondly, a class of materials which are very resistent to any conventional description (called "strongly correlated") will be treated by finding the structure of very; small clusters of these very difficult materials, and using these cluster results as a basis for determining the properties of the corresponding bulk materials.
