DERIVATION AND APPLICATION OF AB-INITIO NB5+-O2- SHORT-RANGE EFFECTIVE PAIR POTENTIALS IN SHELL-MODEL SIMULATIONS OF KNBO3 AND KTAO3

Autor(en): DONNERBERG, H
EXNER, M
Stichwörter: ALKALI-HALIDES; CLUSTERS; COMPUTER-SIMULATION; CU+; DEFECTS; ENERGIES; FERROELECTRICITY; INTERIONIC POTENTIALS; LINBO3 CRYSTALS; Materials Science; Materials Science, Multidisciplinary; OXIDES; Physics; Physics, Applied; Physics, Condensed Matter
Erscheinungsdatum: 1994
Herausgeber: AMERICAN PHYSICAL SOC
Journal: PHYSICAL REVIEW B
Volumen: 49
Ausgabe: 6
Startseite: 3746
Seitenende: 3754
Zusammenfassung: 
We derive an ab initio Nb5+-O2- short-range pair potential appropriate to KNbO3, which is based on suitable cluster Hartree-Fock calculations. The cluster to be chosen must necessarily represent a larger portion of KNbO3 crystals than a lone Nb5+O2- pair embedded in the appropriate Madelung potential. Our final Hartree-Fock pair potential derived from (embedded) (NbO6)7- cluster calculations is in good agreement with a corresponding empirical potential obtained from fitting procedures to macroscopic properties of KNb3O8. Both potentials generate the cubic phase of KNbO3. Finally, the implications of these two Nb5+-O2- pair potentials are discussed by means of shell-model defect simulations in KNbO3 and KTaO3.
ISSN: 01631829
DOI: 10.1103/PhysRevB.49.3746

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