Physical review. B, Solid state
Equations of state for bicritical points. III. Cubic anisotropy and tetracriticality
Eytan Domany, Michael Ellis Fisher
Abstract
Crossover scaling functions for a two-component spin system with quadratic anisotropy $g$ and cubic anisotropy $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{v}$ are calculated to first order in $\ensuremath{\epsilon}=4\ensuremath{-}d$ and in $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{v}$, near the transitions within the ordered phases below the multicritical point ($T={T}_{m},g=0$). Emphasis is placed on the mechanism by which the system is driven to bicritical or tetracritical behavior by the dangerous irrelevant variable $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{v}$. Explicit expressions and graphs for the various thermodynamic scaling functions are presented.