Effects of double-atom vacancies on the electronic properties of graphyne: a DFT investigation

Vacancy defects are one of the key impurities that strongly affect the properties of materials. In the present study, some different double-atom vacancies were introduced into α-graphyne (Gy), βGy, and γGy, depending on their own structural characteristics. Subsequently, density functional theory (DFT) calculations were carried out to evaluate the changes in the structural and electronic properties induced by the double-atom vacancies. The results indicated that the double-atom vacancies only lead to an in-plane structural rearrangement of all three of the Gy systems. It was further revealed that the position of the double-atom vacancies is a crucial factor in the manipulation of the electronic properties of αGy and βGy as compared with γGy. Our work is expected to yield new Gy materials with the desired properties obtained by altering the position of induced double-atom vacancies.