6533b82bfe1ef96bd128d47b
RESEARCH PRODUCT
Quantum Mechanical Modelling of Pure and Defective KNbO3 Perovskites
M. G. StachiottiSilvia TinteC. O. RodriguezEugene A. KotominN. E. ChristensenG. BorstelRoberts I. EglitisDmitri NovikovAndrei Postnikovsubject
Condensed Matter::Materials ScienceCondensed matter physicsAb initio quantum chemistry methodsPhysics::Atomic and Molecular ClustersAb initioDensity functional theoryElectronic structureLocal-density approximationPolaronMolecular physicsFerroelectricityQuantumMathematicsdescription
Ab initio electronic structure calculations using the density-functional theory (DFT) are performed for KNbO3 with and without defects. Ferroelectric distortive transitions involve very small changes in energies and are therefore sensitive to DFT-approximations. This is discussed by comparing results obtained with the local density approximation (LDA) to those where generalized gradient approximations (GGA) are used. The results of ab initio calculations for F-type centers and bound hole polarons are compared to those obtained by a semiempirical method of the Intermediate Neglect of the Differential Overlap (INDO), based on the HartreeFock formalism. Supercells with 40 and 320 atoms were used in these two approaches, respectively. The relevant experimental data are discussed.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2000-01-01 |