Displacive and order–disorder behavior of KDP-type ferroelectrics on the local scale

The modified strong dipole–proton coupling (MSDPC) model, which predicted several static and dynamic dielectric properties of KH2PO4 or KDP-type ferroelectrics, was used to investigate the properties of these crystals on the local scale. Results calculated by molecular dynamics (MD) simulation show that both order–disorder and displacive characteristics of one PO4 dipole are present in KDP and KD2PO4 (DKDP). These results correlate with experimental data from NMR and neutron scattering studies of local properties.