Publication No.71



C. Zambrano, A. Sánchez, L. M. Prócel, A. Stashans. Structural 
and electronic properties of PbZrxTi1-xO3 (x=0.5, 0.375): a 
quantum-chemical study - Int. J. Quant. Chem., 2003, Vol. 95, p. 37. 

Abstract:
	The structural and electronic properties of the PZT 
materials PbZr0.5Ti0.5O3 and PbZr0.375Ti0.625O3 were studied by 
means of a Hartree-Fock quantum-chemical method which 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> directions 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-6p atomic orbitals with 
less important contributions of Zr-4d and Ti-3d states.  The 
upper valence band (UVB) for the cubic phases was mostly Pb-6s 
in nature, with minor contribution of O-2p atomic orbitals.  
The tetragonal phase on the other hand was formed by Pb-6s with 
some contribution of admixed O-2p with Zr-4s and Ti-3s atomic 
orbitals.  The optical band gap (delta SCF method) was found to 
decrease going from the cubic to the tetragonal phase in both 
titanates.




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