Mechanical, Electronic, and Optical Properties of 8-16-4 Graphyne: A 2D Carbon Allotrope with Dirac Cones

Graphene's success has led to the theoretical prediction and experimental synthesis of various 2D carbon-based allotropes. To explore the mechanical, structural, electronic, and optical properties of 8-16-4 graphyne, we employed density functional theory using the GGA/PBE approach, ab initio molecular dynamics (AIMD), and classical reactive molecular dynamics simulations. Our AIMD results indicate that this material demonstrates excellent dynamical and thermal stabilities. It has a formation energy of −8.57 eV/atom and an elastic moduli of 262.37 GPa. Regarding its band structure, this graphyne analogue is a semimetal with two Dirac cones. It also exhibits transparency and intense optical activity in the infrared region. Notably, the band structure of 8-16-4 graphyne remains practically unchanged at moderate strain regimes. To our knowledge, this is the first known 2D carbon allotrope to exhibit such behavior.