The local structure around the Nd impurity incorporated into the crystal matrix: An ab initio study

The local structure around the Nd impurity introduced at the Bi site in the Bi4Ge3O12 compound is theoretically investigated by density-functional theory based augmented plane wave method. A set of parameters that completely describes the Nd neighborhood is calculated by treating the Nd 4f electrons either as localized or as delocalized. In both cases the local structure was dominantly determined by the Nd departure from the ideal host position along the trigonal axis. Displacement occurs in the direction towards the center of the Oxygen octahedron around the Nd.