Electronic structure and lattice distortions in PbMg1/3Nb2/3O3 studied with density functional theory using the linearized augmented plane-wave method

We investigated the local structural distortions of PMN(PbMg1/3Nb2/3O3) within the density functional theory using the linearized augmented plane-wave method. Structural relaxations were performed on 30 atom unit cells with B-cations arranged in 1:1 chemical ordering along [111]. The direction and magnitude of Mg and Nb off-centering within O-6 octahedral cages and Pb within its cage as well as electronic structures were examined. The results are discussed in terms of the Nb 4d-O 2p and Pb 6p-O 2p hybridizations and their interplay. A significant role is found for the on-site Ewald potential of different Nb sublattices, which is correlated with the off-centering.