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

Figure 4

Fundamental band gaps for the cubic phase of calculated with different exchange-correlation functionals (see Table 8). The HSE- band gaps are calculated for PBEsol equilibrium geometries and depend on the fraction of exact exchange . The solid lines are intended to guide the eyes. The dashed lines mark the size of the fundamental LDA, PBE, and PBEsol band gaps.