Density functional calculations on the magnetic properties of uranium surfaces.

摘要

Recently, there has been an increased interest in first-principles calculations of the actinides as well as in finding new materials which display surface magnetism. This thesis presents a combination of both problems in an investigation of uranium metal and its properties, of which the most interesting is the surface magnetism for (001) surface.; The existence of a magnetic moment on the uranium (001) surface is predicted by performing density functional calculations for a slab geometry in the generalized gradient and local spin density approximations including spin orbit coupling. It is shown that the surface ferromagnetic phase is energetically favored for all geometries. The calculated total magnetic moment, 0.65μ _B, should be observable in spin polarized photoemission, magnetic circular dichroism or Kerr effect experiments.; Also presented in this dissertation is a study of structural properties of uranium. It was found that the observed high-temperature uranium phase, the body centered cubic structure, is unstable at zero temperature.; The work was done in the Center for Data Intensive Computing, at the Brookhaven National Laboratory, on a Beowulf computer cluster. The same cluster was utilized in the investigation of transverse magnetic defect modes in two-dimensional triangular-lattice photonic crystals.