Figure 5
Visualization of selected tight-binding modes of BaTiO3 in the P4mm space group. For Ti (Wyckoff position 1b), all three basis vectors are shown, and they demonstrate the retained 3N degrees of freedom, as the pair that together transform as E are allowed to have independent amplitudes. For the O1 site (Wyckoff position 2c), the A1 and B1 modes each join two O-atom positions, but 3N degrees of freedom are retained for the two atoms generated from that Wyckoff position, noted by the six independent modes. While the E pairs will transform together if the local symmetry is also P4mm, all amplitudes are allowed to vary independently in this analysis. |