6533b821fe1ef96bd127c0f7
RESEARCH PRODUCT
Semi-empirical calculations of the Nb-ion positions in doped crystals
R. I. EglitisR. I. EglitisSimon DorfmanEugene A. KotominEugene A. KotominG. Borstelsubject
Phase transitionChemistryDopingElectronic structureCondensed Matter PhysicsMolecular physicsX-ray absorption fine structureIonCondensed Matter::Materials ScienceCrystallographyImpurityAb initio quantum chemistry methodsGeneral Materials SciencePerovskite (structure)description
The atomic and electronic structures of Nb impurities in doped perovskite KTaO3 crystals are calculated using the semi-empirical quantum chemical method of the intermediate neglect of the differential overlap (INDO) and a supercell model. When seven Ta ions are replaced by seven Nb ions, the latter clearly demonstrate self-ordering effects which are related to the experimentally observed impurity-induced phase transition. A single Nb impurity reveals an off-centre displacement which is very close to that found in XAFS experiments. The relevant energy gain is very small, approximately 0.0375 eV, which is much smaller than the Nb-clustering energy gain (0.12 eV). These results led us to the conclusion that such self-ordered high-symmetry seven-ion clusters are stable in a KTaO3 matrix.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1998-07-20 | Journal of Physics: Condensed Matter |