Hard spin mean field theory of 3D stacked-triangular-lattice system

Abstract

Closed form solution of ‘Hard spin mean field theory’ is constructed and applied to ‘Three dimensional stacked-triangular-system’. The phase diagram of this system is examined. ‘Free energy’ is calculated to reveal the thermodynamically stable state in the phase diagram. A new second order phase transition line is found near the zero external magnetic field. Strong evidence is found for the tricriticality point behaviour in the multicritical region.