AB Initio Approach to the Ferroelectric Properties of ABO 3 Perovskites: The Case of KNbO 3

Autor: Ph. Baranek, Roberto Dovesi
Rok vydání: 2002
Předmět:
Zdroj: Ferroelectrics. 268:155-162
ISSN: 1563-5112
0015-0193
DOI: 10.1080/00150190211078
Popis: The ferroelectric perovskite KNbO 3 is investigated at the ab initio quantum mechanical level, by using the CRYSTAL program and a gaussian type basis set. A set of well localized Wannier functions (LWF) is obtained by applying a unitary transformation to the delocalized crystalline orbitals describing the ground state. The spontaneous polarization, the Born effective charges and the piezo-electric constants obtained from the LWF with various hamiltonians are compared. The calculations are performed at the Hartree-Fock (HF), density functional (DFT) and hybrid (B3LYP) level of theory. As regards DFT, the local density (LDA) and generalized gradient (GGA) approximations are used.
Databáze: OpenAIRE