Electronic, optical, and water solubility properties of two-dimensional layered SnSi2N4 from first principles

In this work, we identify a two-dimensional layered nitridosilicate ${\mathrm{SnSi}}_{2}{\mathrm{N}}_{4}$ in hexagonal structure via first-principles calculations. From the total energy calculations, ${\mathrm{SnSi}}_{2}{\mathrm{N}}_{4}$ is thermodynamically stable. The dynamic stabilities are demonstrated by the phonon spectrum and molecular-dynamics simulations. The ${\mathrm{SnSi}}_{2}{\mathrm{N}}_{4}$ exhibits semiconducting behavior with a direct band gap of 3.70 eV $({\mathrm{GW}}_{0})$, Young's modulus of 478 GPa and breaking strength of 47 GPa, and electron mobility of $2736\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{2\phantom{\rule{4pt}{0ex}}}{\mathrm{V}}^{\text{--}1\phantom{\rule{4pt}{0ex}}}{\mathrm{s}}^{\text{--}1}$ (Perdew-Burke-Ernzerhof). According to the absorption spectra, ${\mathrm{SnSi}}_{2}{\mathrm{N}}_{4}$ presents good absorption of ultraviolet light with high energy. The chemical stability of aqueous solution is verified by the molecular-dynamics simulations.