Effect of configuration and biaxial strain to electronic structure of half-fluorinated graphene

Abstract

Mechanical stability and equilibrium structure of half-fluorinated graphene with different configurations of fluorine atoms on the surface of graphene are investigated by density functional theory (DFT). Phonon density of states reveals that the half-fluorinated graphene with chair, boat, zigzag, chair*, and boat* structures are stable. Band structures of the half-fluorinated graphene are calculated by DFT with generalized gradient approximation. Band gaps are corrected by the GW method. Half-fluorinated graphene with chair, zigzag, and chair* structures are metallic. Half-fluorinated graphene with chair structure is spin-polarized. Half-fluorinated graphene with boat and boat* structures are indirect band gap semiconductors and the GW band gaps of them are 5.147 eV and 5.648 eV respectively. Structural and electronic properties of half-fluorinated graphene under a series of biaxial strain are studied. A tensile strain larger than 6% can open an indirect band gap for half-fluorinated graphene with chair structure. Band gap type of half-fluorinated graphene with boat* structure undergoes an indirect-to-direct transition under compressive strain.