The electronic band structure (Figure ) exhibits similar curvature near both the valence-and conductionband edges. The charge-carrier effective masses at the band edges are tabulated in Table . The band structure projected onto the structure. This image was prepared using VESTA. is highly anisotropic with respect to the in-plane (xy) and out-of-plane (z) directions. The bands along the Γ-Z and N-P directions, which correspond to the z direction in real space, are flat and heavy, with effective electron and hole masses of 84 m e along the Γ-Z direction calculated from parabolic fits of the band edges. Conversely, the bands associated with the in-plane directions are more disperse and several orders of magnitude lighter at the band edges, resulting in effective electron masses of 0.279 m e (Γ-X) and 0.312 m e (Γ-N) and hole masses of 0.538 m e and 0.554 m e along the same directions.