Stability and physical properties of net-Y-Si from first-principles calculation

Abstract

We predicted the stability, optical properties, and ability to store sodium of a novel two-dimensional silicene-like material net-Y-Si by embedding both six-membered and four-membered rings into silicene. The electronic band structure shows the density of states near the Fermi level are not zero, which means net-Y-Si is metallic and possesses good conductivity. This is caused by the sp2 hybridized silicon atoms in the hole conjugated structures, which makes net-Y-Si more stable, and the p bonding characteristics more pronounced. net-Y-Si has a warp with the height 0.328 Å and larger voids. Then, we demonstrated its stability through molecular dynamics simulations and phonon dispersion analysis. According to our prediction, the light absorption capacity of the material exhibits anisotropy. The static dielectric constant of net-Y-Si is nearly 8 times that of carbon-based material net-Y. Because of the good conductivity, carrier mobility, and good light absorption ability in the visible and ultraviolet regions, it gives the material the potential to become a visible light wave tube material. In terms of sodium storage, net-Y-Si has an adsorption energy of −3.26 eV on average. The migration of sodium on the material exhibits significant anisotropy, and the migration barrier is only 0.214 eV. Therefore, net-Y-Si also has the potential to become an electrode material for sodium ion batteries.