First principle study of SiO$_2$ bilayer on metallic substrates

Silicates in zeolite form have wide applications in catalysis: they have porous structures with large internal surface areas. However, it is hard to characterize such internal surfaces with atomic resolution experimentally. Therefore, a 2D form of silica provides an interesting model system that can be probed using real-space methods such as scanning tunneling microscopy (STM). In fact, 2D SiO$_2$ bilayers can be created experimentally. Both crystalline and amorphous bilayers have been grown on various metallic substrates. Due to the fully saturated nature of the Si-O bonds, it has been argued that the SiO$_2$ bilayer and substrate interact weakly: however, the substrates can enforce epitaxial strain on the bilayer. In this work, we investigate to what extent metallic substrates (e.g. Ru and Pd) affect the stable morphologies of SiO$_2$ bilayers by using \textit{ab initio} density functional theory (DFT). We are particularly interested in seeing how strain in the bilayer competes with substrate interactions and the nature of the resulting bilayer structures. This work is supported by the National Science Foundation through grant NSF DMR-1506800.