Application of the Transverse Ising Model to CsH₂PO₄ and CsD₂PO₄

Abstract

The ferroelectric phase transitions in CDP and DCDP are studied on the basis of the quasi-one-dimensional transverse Ising model. The dielectric susceptibilities are calculated on the assumption that the ratio of the intar-chain interaction to the tunneling energy is very large, and compared with the experimental data. Without the introduction of unnatural large difference in other model parameters between CDP and DCDP, a satisfactory agreement has been obtained for the static as well as dynamic susceptibilities.