Multiple Dirac cones in BN co-doped β-graphyne

Abstract

BN co-doped β-graphyne (β-GY) was investigated using state-of-the-art theoretical calculations. β-GY with sp or sp² carbon pairs substituted by BN pairs was referred to as β-GY_BN1 or β-GY_BN2, respectively. Their dynamic and thermal stabilities were confirmed by phonon spectrum calculations and ab initio molecular dynamics (AIMD) simulations. Interestingly, the ternary hybrid BCN monolayer β-GY_BN1 was predicted to be semimetallic with multiple distorted Dirac cones at the Fermi level, including crossed ones and gapped ones. Their infrared (IR) and Raman spectra were simulated to serve as fingerprints for experimental identification. It was also found that hydrogen atom adsorption would depress the energy bands of β-GY_BN1, and made other isotropic Dirac cones crossed at the Fermi level. Our study not only indicates the potential applications of BN co-doped β-GY in future spintronics and optoelectronics, but also implies a possible approach to explore novel semimetallic Dirac materials.