Electronic and Optical Properties of Sodium Niobate: A Density Functional Theory Study

Figure 6

NaNbO₃ dielectric functions for the crystalline phases at room temperature and below calculated using the PBEsol functional revised for solids [18] (solid lines). The real (green) and imaginary (orange) parts of the dielectric functions for (a) the rhombohedral phase (SG 161), (b) the orthorhombic phase (SG 57), and (c) the monoclinic phase (SG 6) are shown. For easier comparison, the dielectric functions of the high-temperature cubic perovskite phase (SG 221) are included in (d). In addition, PBE0 hybrid functional calculations based on the PBEsol ground state structures are shown with dashed lines.