The Investigation of the Ferroelectric Phase Transition in Cluster Systems of Order–Disorder Type

Abstract

AbstractThe description of second‐order ferroelectric phase transitions in cluster systems of order–disorder type in the frames of the collective variables method is proposed. By means of the canonical Hubbard operator technique the Ising‐like form of the Hamiltonian is obtained. The partition function is represented as a functional integral over collective variables. The classification of collective variables according to their role in forming of the ferroelectric order parameter is made. For a consistent consideration of critical fluctuations of the order parameter a non‐Gaussian, quartic basic measure density is obtained.