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

Table 9

Fundamental band gaps for the different phases of with the HSE-30 functional from the band structures in Figure 5 compared to experimental values.

Phase	HSE-30		Expt.
	Transition	Band gap (eV)	Band gap (eV)
		3.14	, ,
P4mm		3.23	,
Amm2		3.59	, ,
Pm		3.63	,
R3m		3.80

[50]; optical gap from absorption spectrum.
[51]; optical gap from UV-vis diffuse reflectance spectrum.
[52]; optical gap from absorption spectrum.
[53]; optical gap from X-ray photoelectron spectrum.
[47]; optical gap from absorption spectrum.
[48]; optical gap from diffuse reflectance UV-vis spectroscopy.