On the problem of the functional representation for cluster ferroelectric systems

Abstract

The problem of phase transition in ferroelectric systems is regarded on the base of non-Gaussian functionals representation. Both short and long range interparticles interactions and external transverse field are taken into consideration. The partition function functional coefficients depends on temperature and energy parameters of a chosen “reference system” (a set of non-interacting with each other intracell groups of particles, so called clusters), while for the usual Ising model they are constants. This circumstance is a source of a rigorous restrictions for the possible reference system parameters, especially, at low temperatures when a quantum peculiarities of the system becomes important. The region of admissible internal and external parameters under which the investigated cluster ferroelectric system remains stable is investigated.

Key Words:

• cluster ferroelectrics
• phase transition
• partition function
• cumulants