Universal collaborative couplings between oxygen-octahedral rotations and antiferroelectric distortions in perovskites

摘要

We identify two elemental interatomic couplings that control the collaborative (as opposed to competing) interaction between the O_6 octahedral rotations (usually called antiferrodistortive or AFD modes) and the antiferroelectric (AFE) displacement patterns of the A-site cations in oxides with the ABO_3 perovskite structure. Straightforward analytical derivations allow us to reproduce and explain the origin of various long-range AFE orders that have been previously found in different phases of several perovskite compounds, all possessing simple or even complex long-range AFD patterns. Our analysis also leads to the prediction of original peculiar combinations of AFD and AFE orders that are awaiting to be observed.