Mechanical Properties of Graphene, Silicen, Germanen and mixtures of them

The mechanical properties of graphene and similar structures i.e. silicone and germanium nanosheets have been studied in this article. All calculations were performed with Quantum Espresso Code. The ultrasoft pseudo potential based on PBE functional was employed to calculate the properties of structures. All structures were optimized and the energy of structures as function of extered stress was calculated. The Yang modulus of all structures were calculated and it was shown that the graphene (C-C structure) and germanene (Ge-Ge structure) have higher and lower Yang modulus respectively. Other structures had values between these two cases. It was seen that the Yang modulus reduced by increasing the volume of unit cell. In Figure 1, the Yang modulus is plotted as function of unit cell volume