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Structural and electronic properties of PbZr x Ti 1‐x O 3 (x = 0.5, 0.375): A quantum chemical study
Author(s) -
Zambrano Cesar,
Sanchez Alfredo,
Procel Luis Miguel,
Stashans Arvids
Publication year - 2003
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10711
Subject(s) - tetragonal crystal system , valence (chemistry) , atomic orbital , electronic structure , chemistry , atom (system on chip) , band gap , crystallography , materials science , atomic physics , condensed matter physics , crystal structure , computational chemistry , physics , electron , organic chemistry , quantum mechanics , computer science , embedded system
The structural and electronic properties of the PZT materials PbZr 0.5 Ti 0.5 O 3 and PbZr 0.375 Ti 0.625 O 3 were studied by means of a Hartree–Fock quantum chemical semiempirical method that employs a periodic large unit cell (LUC) model. The atomic relaxation observed upon introduction of the Zr impurities resulted in outward oxygen atom displacements along the 〈100〉 direction for the cubic phases and varied oxygen and lead atom movements for the tetragonal structures. For these materials, the conduction bands (CB) were composed mainly of Pb 6 p atomic orbitals with less important contributions of Zr 4 d and Ti 3 d states. The upper valence band (UVB) for the cubic phases was mostly Pb 6 s in nature, with minor contribution of O 2 p atomic orbitals. The tetragonal phase on the other hand was formed by Pb 6 s with some contribution of admixed O 2 p with Zr s atomic orbitals. The optical band gap (ΔSCF method) was found to decrease going from the cubic to the tetragonal phase in both titanates. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 95: 37–43, 2003