The electronic, optical, and thermodynamical properties of tetragonal, monoclinic, and orthorhombic M3N4 (M = Si, Ge, Sn): A first-principles study
Chen Dong1, †, Cheng Ke2, Qi Bei-Ying1
       

(color online) Real part of dielectric function for different M3N4 (M=Si, Ge, Sn) polymorphs: (a) tetragonal; (b) monoclinic; (c) orthorhombic. Imaginary part of dielectric function for different polymorphs: (d) tetragonal; (e) monoclinic; (f) orthorhombic. The black/dashed, blue/solid, and red/solid curves represent the Si3N4, Ge3N4, and Sn3N4 compounds, respectively.