Dimensionality Effects on the Multicritical Phase Diagrams of the Blume-Emery-Griffiths Model with Repulsive Biquadratic Coupling: Mean-Field and Renormalization-Group Studies

摘要

Six new phase diagrams, including a novel multicritical topology and two new ordered phases, are obtained by the global mean-field theory of the spin-1 Ising model with only nearest-neighbor interactions, for negative biquadratic couplings. Renormalization-group studies indicate a threshold spatial dimension, above and below which different sequences of phase diagrams occur.