Consistent Atomic Geometries and Electronic Structure of Five Phases of Potassium Niobate from Density-Functional Theory

Figure 3

Correlation between the equilibrium unit-cell volume and the total-energy difference per formula unit with respect to the cubic phase calculated with different exchange-correlation functionals. The solid lines are intended to guide the eyes. The dashed bars indicate the total volume and energy ranges encompassing all five phases for a particular functional.