Mechanical properties of graphdiyne sheet

The influences of strain to the energetic and electronic properties of graphdiyne are investigated based on first-principles calculations. The elastic parameters of graphdiyne are determined by total energy calculation. Compared to graphyne, graphdiyne is softer because it has less C-C bonds. Moreover, the band gap of graphdiyne is tunable under uniform strain. It monotonously increases with increasing strain value, which originates from the decreased orbital overlap between C atoms when strain increases.