  When spatial constraint for the constituents (e.g., atom or particle) of
system is once given, disordered structure for non-interacting system in
equilibrium states is symmetric with respect to equiatomic composition.
Meanwhile, when the interaction between constituents is introduced, this
symmetry is typically broken, naturally appearing compositional asymmetry.
Although this asymmetry, depending on temperature, comes from multibody
interactions in the system, we here clarify that the asymmetry near equiatomic
composition can be universally well-characterized by two specially selected
microscopic structure, which can be known a priori without any information
about interactions or temperature: The key role is the class of spatial
constraint. Based on the facts, we provide analytical expression of temperature
dependence of disordered structure, and demonstrate its validity and
applicability by predicting short-range order parameters of practical alloys
compared with full thermodynamic simulation.
