The effect of pressure on the electronic and optical properties of hydrogenated graphene: a first-principles study

Abstract

First-principle calculations are performed to study the structural, electronic, and optical properties of chair-structured hydrogenated graphene (C-graphane) under different hydrostatic pressures. The lattice constants, bond lengths, bond angles, energy band gap, and binding energy are calculated in the pressure range of 0–300 GPa. The results show that C-graphane is stable up to 250 GPa but becomes unstable at 300 GPa, with direct band gap behavior up to 30 GPa but an indirect band gap at 35 GPa. The optical properties such as the static dielectric constant e(0), refractive index n(0), birefringence ∆n(0), and plasmon energy (ћωp) are studied at different hydrostatic pressures of 0 GPa, 15 GPa, and 30 GPa for the first time. The calculated values of all the parameters are in reasonable agreement with available experimental and reported values.