Metal decorated graphdiyne: A first principle study

In this work, we performed first principles calculations based on self-consistent charge density functional tight-binding to investigate mechanical and electronic properties of the optimized graphdiyne sheet, nanoribbons and transition metal decorated with Ag, Fe and Co atoms in the different sites. Then we calculated electronic properties of the graphdiyne sheet under uniaxial elastic strain in two different crystal directions. It is shown that the carbon bond length values for the graphdiyne structure are agreeable with experimental and other theoretical values. Our results show that the charge transferred to the graphdiyne from Ag and Fe atoms but to the Co decorated charge transferred to the Co atom from the graphdiyne. From the results, it can be seen that the graphdiyne is a direct semiconductor with doubly degenerated for both the valence band maximum and the conduction band minimum in the 6C hole site. Also, by Metal decorated of the graphdiyne, the structures become also direct semiconductor for the Ag decorated and indirect for Co and Fe decorated for the 6C- hole, top and bridge sites while the structure have metallic behavior for the 18C- hole site. Our results from the band structure of the GDY nanoribbons with the size of N = 1, 2, 3 and 4, indicate that all of them are nonzero band gaps at the Γ point. It can be seen that the energy gap decreases with increasing of nanoribbons size. Finally, we found that the gap energy increase with applying strain and also the structure remain direct semiconductor.