Atomic scale DFT simulations of point defects in uranium nitride

Atomic scale density functional calculations are used to predict the behaviour of defects in uranium mononitride (UN). Two different density functional codes (VASP and CASTEP) were employed with supercells containing from 8 to 250 atoms (providing a significant range of defect concentrations). Schottky and nitrogen Frenkel point defect formation energies, local lattice relaxations and overall lattice parameter change, as well as the defect induced electronic density redistribution, are discussed.

[1]  F. Wastin,et al.  Real structure and magnetic properties of UN thin films , 2005 .

[2]  C. Catlow,et al.  Point defect and electronic properties of uranium dioxide , 1977, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[3]  Hj. Matzke,et al.  Science of advanced LMFBR fuels , 1986 .

[4]  Matt Probert,et al.  First-principles simulation: ideas, illustrations and the CASTEP code , 2002 .

[5]  R. P. Agarwala.  Diffusion processes in nuclear materials , 1992 .

[6]  M. Brooks,et al.  Electronic structure of NaCl-type compounds of the light actinides. I. UN, UC, and UO , 1984 .

[7]  R. A. McDonald,et al.  The Structures of the Carbides, Nitrides and Oxides of Uranium1 , 1948 .

[8]  H. Matzke,et al.  Self-diffusion of plutonium in uranium-plutonium mononitride , 1978 .

[9]  L. Gerward,et al.  A new high-pressure phase of uranium nitride studied by X-ray diffraction and synchrotron radiation , 1985 .

[10]  F. Jollet,et al.  Plane-wave pseudopotential study of point defects in uranium dioxide , 2001 .

[11]  T. L. Bihan,et al.  New investigation of pressure-induced rhombohedral distortion of uranium nitride , 2003 .

[12]  John H. Harding,et al.  The calculation of defect parameters in UO2 , 1986 .

[13]  Michel Freyss,et al.  Point defects in uranium dioxide: Ab initio pseudopotential approach in the generalized gradient approximation , 2005 .

[14]  N. N. Greenwood.  Ionic Crystals, Lattice Defects and Nonstoichiometry , 1968 .

[15]  Richard L. Martin,et al.  Hybrid density-functional theory and the insulating gap of UO2. , 2002, Physical review letters.

[16]  The nitrogen vacancy in aluminium nitride , 2006 .

[17]  H. Monkhorst,et al.  SPECIAL POINTS FOR BRILLOUIN-ZONE INTEGRATIONS , 1976 .

[18]  Effect of dielectric polarization on the properties of charged point defects in insulating crystals: the nitrogen vacancy in AlN , 2004 .

[19]  S. Yamanaka,et al.  Molecular dynamics study of mixed oxide fuel , 2001 .

[20]  Wang,et al.  Accurate and simple analytic representation of the electron-gas correlation energy. , 1992, Physical review. B, Condensed matter.

[21]  G. Henkelman,et al.  A fast and robust algorithm for Bader decomposition of charge density , 2006 .