  We investigate the mechanism of formation of supermixed soliton-like states
in bosonic binary mixtures loaded in ring lattices. We evidence the presence of
a common pathway which, irrespective of the number of lattice sites and upon
variation of the interspecies attraction, leads the system from a mixed and
delocalized phase to a supermixed and localized one, passing through an
intermediate phase where the supermixed soliton progressively emerges. The
degrees of mixing, localization and quantum correlation of the two condensed
species, quantified by means of suitable indicators commonly used in
Statistical Thermodynamics and Quantum Information Theory, allow one to
reconstruct a bi-dimensional mixing-supermixing phase diagram featuring two
characteristic critical lines. Our analysis is developed both within a
semiclassical approach capable of capturing the essential features of the
two-step mixing-demixing transition and with a fully-quantum approach.
