Fig. 5: Theoretical phase diagram.
From: Multiple magnetic orders in LaFeAs1-xPxO uncover universality of iron-pnictide superconductors
Evolution of Landau parameters \({\alpha }_{i}\) and \(g\) (constants from the quadratic and quartic parts of the Landau free energy expansion) as a function of change in Fermi momentum, \(\triangle {k}_{F}/{k}_{F}\). This models the evolution of the leading magnetic instability with P substitution on the As site, with larger P concentrations corresponding to a larger Fermi surface. The left vertical axis represents the relative difference in these values for the constants, \(\triangle \alpha\), and the right axis represents values for \(g\). The transitions between different instabilities correspond to when g drops below zero and when \({\alpha }_{3}-{\alpha }_{1}\) becomes smaller than \({\alpha }_{2}-{\alpha }_{1}\). Inset is a snapshot of the Fermi surface in the 2Fe/unit cell.
