Unveiling the topological structure and optical properties of Ge2N2O and Sn2N2O: DFT, Hirshfeld topological surfaces, and their role in advanced materials

Abstract

The structure-optical features of Ge₂N₂O and Sn₂N₂O oxynitride single crystal were studied by Density Functional Theory (DFT) and Hirshfeld topological surface (HTS) analysis. The results reveal that Sn₂N₂O outstrips Ge₂N2O in terms of a dielectric function, and UV reflectivity peaked 125<λ < 225 nm. Also, discrepancies in the refractive index n∗ = n + iκ as a function of photonic energies shows dependency on different polarization planes. The structural analysis underlines the importance of metal-nitrogen interactions, with average Sn-N (i.e., 2.0683 Å) and Ge-N (i.e., 1.8552 Å) bonds being vital for the stability of these materials. The HTS analysis also indicates that Sn-N and Ge-N interaction is 49.7 % and 49.0 % highlighting their profound effects lattice structure, and other material properties. The current study pointed to the potential of these two crystals for applications in advanced semiconductor and optoelectronic technologies for future innovations in material design.