Figure 1: Schematic phase diagram near a Mott transition.
From: Superconductivity at the border of electron localization and itinerancy
In this zero-temperature phase diagram, the red point located on the U/W axis refers to the point of the Mott transition, whereas the purple shading illustrates the regime that has strong anti-ferromagnetic correlations. The parent compounds of alkaline iron selenides and iron pnictides are located in the vicinity of, albeit on the two sides of, the Mott transition. Superconductivity occurs at non-zero carrier doping, with the optimal doping located in the region indicated by the arrows.
