DENSITY FUNCTIONAL THEORY CALCULATIONS FOR FORMATION ENERGIES AND STRUCTURAL CHARACTERISTICS OF La OR Gd DOPED Bi2WO6 SYSTEMS
Tóm tắt
By using first-principles calculations based on density functional theory, we investigate the doping effect of rare-earth elements (La and Gd) in Bismuthtungstate Bi2WO6 on structural characteristics. Firstly, the formation energies for
doping configurations are calculated in order to carry out the most stable one. The obtained results prove that doping to sixteen Bi sites needs the similar formation energies due to the geometrical symmetry of the origin material. Secondly, the optimized structures of La- and Gd-doped systems are achieved by relaxation calculations. Finally, by comparison the lattice parameter between two doped systems, we find the insignificant changes in lattice constants, and hence, cell volumes. This can be attributed to the similarity in ionic radii of dopants (La or Gd) and host (Bi) ion.
