Electronic Structure Studies and Photocatalytic Properties of Cubic Bi_1.5ZnNb_1.5O₇

Table 2

Comparison of parameters obtained with DFT-GGA calculations for BZN random, ordered, and partially ordered solid solutions.

BZN solid solution	Calculated symmetry	Spin polarization	Lattice length (Å)	Lattice angles (°)	CASTEP formation energy (eV)	CASTEP normalized energy (kJ/mol)	Band gap (eV)
Random	Cubic	No spin	10.48	90			No gap
	Cubic	Spin = 2	10.44	90			2.7; 2.9
	Primitive	No spin	7.41	60			No gap
	Primitive	Spin = 2	7.41	60			2.9
Ordered	C-centered orthorhombic	No spin	10.86; 10.86; 10.71	90; 90; 89.49			2.2
	Triclinic	No spin	10.87; 10.74; 10.85	90.03; 90.79; 89.93			2.2
	Triclinic	Spin = 2	10.87; 10.74; 10.84	89.99; 90.82; 90.00			2.2
Partially ordered (B site)	Orthorhombic	No spin	7.61; 7.52; 10.82	90			2.2
	Orthorhombic	Spin = 2	7.61; 7.52; 10.76	90			2.2
Partially ordered (A site)	Cubic	No spin	10.58	90			No gap

The input structure is adapted from the cubic BZN cif ( Å).
The input structure converted to primitive has lattice parameter 7.46 Å with 60° angles.
The CASTEP program labels the result structure as C-centered orthorhombic even though there is a small deviation from 90° in one of the angles.
Spin polarization in this case resulted in job failure during calculations.