Structure properties of La2Zr2O7 crystal doped with rare-earth ions RE3+: Ab initio calculation.

In this paper we investigated the impurity center local structure by simulation of the structural proprieties of the rare-earth impurity centers RE3+/Bi3+ in lanthanum zirconated La2Zr2O7. Rare-earth ion RE3+/Bi3+ replaces the cation La3+ and determines distortions of the La2Zr2O7 crystal lattice near the impurity center. These distortions characterized by radial and angular displacements of anions were investigated by ab initio calculations. We have employed the MO LCAO approach, in the frame of DFT method as it is implemented in the CRYSTAL17 software for periodic systems, using the hybrid functional PBE0. Since the main contribution to the crystal field on the rare-earth impurity ions comes from its nearest neighbors, the distance "rare-earth ion – ligand" and coordinates of the ligands (oxygen ions) near the impurity centers are calculated. The obtained results are discussed and compared with experimental data and the agreement is quite satisfactory. [ABSTRACT FROM AUTHOR]