Molecular dynamics study on the structure and properties of silicon-graphdiyne

A study to shed light on the existence of silicon-graphdiyne as well as their stability, structural and other properties, has been carried out using an efficient semi-empirical Hamiltonian scheme based on quantum mechanics. Its most stable structure is a single planar structure with a lattice constant of 12.251 Å. The system occurs structural phase transition at 1520 K. When the temperature is above 1520 K, the basic structure will be destroyed, While the temperature is below 1520 K, the system can restore its initial structure. It is found that sp hybridization exists between Si and C atoms in this conjugated structure. The study of pair distribution function shows that sp bond length is about 1.58 Å. The sp hybridization would gradually transform into other forms of hybridization at high temperatures. Our calculation indicates that delocalized π-bonds exist in this system and all the lengths of Si-C bonds tend to be more uniform. The energy gap is 1.416 eV. LUMO and HOMO energy levels are 0.386 eV and –1.03 eV respectively. It is found that the silicon-graphdiyne should be n-type material.