Pb-driven anti-ferroelectric phase in Pb(Mg1/3Nb2/3)O-3: First-principle study

摘要

Density functional calculations are used to investigate the role of Pb displacement in the formation of anti-ferroelectric phase in Pb(Mg1/3Nb2/3)O-3. Order and disordered supercells, both are used. Through geometry optimization without symmetry imposed, the two supercells are found to be anti-ferroelectric. Displacement of cations are analyzed and it is shown that asymmetry of Pb's next-nearest B-site shell is probably the reason for anti-parallel displacement of Ph. A-B-site, B-site-O bond distances and O-6 octahedral volumes are also calculated. (C) 2007 Elsevier Ltd. All rights reserved.