MONTE-CARLO SIMULATIONS OF THE PHASE-TRANSITIONS IN THE RB2ZNCL4 CRYSTAL

The model of the order- disorder phase transitions in Rb3ZnCl4 is studied. In this model BX(4) group has a four equlibrium orientations in a disordered hexagonal phase. The constants of the interaction between ordering BX(4) groups are calculated in the framework of the electrostatic model. It is shown that these constants have a competitive nature. The Monte-Carlo method is applied to study the successive phase transitions hexagonal double right arrow orthorombic double right arrow incommensurate double right arrow commensurate ferroelectric phases.