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.