Lower and Upper Bound Estimates of Material Properties of Pristine Graphene: Using Quantum Espresso

Abstract

In this paper, the basic groundstate (T = 0) properties of pristine graphene are calculated using first principles with the aid of Quantum Espresso (QE). QE software suite is a tool based on ab initio quantum chemistry methods to obtain the electronic structure for materials modeling. It is an open source package built basing on the formalism of density functional theory (DFT). Using QE, the band structure, cohesive energy, and second-order elastic constants are estimated for a pristine graphene. Upper bound estimates based on the generalized gradient approximation (GGA) and lower bound estimates based on local density approximation (LDA) are obtained. The cohesive energy is found to be −7.917 eV/atom using LDA and −5.673 eV/atom using GGA. Further, the elastic properties are determined using a post-processing tool ElaStic. The second-order elastic stiffness C 11 is found to be 491.5, and 506.7 GPa using LDA and GGA approaches, respectively.