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The importance of electron correlation in graphene and hydrogenated graphene
, Article European Physical Journal B ; Volume 88, Issue 10 , October , 2015 ; 14346028 (ISSN) ; Jafari, S. A ; Sharif University of Technology
springer berlin
2015
Abstract
Local density approximation (LDA) and Green function effective Coulomb (GW) calculations are performed to investigate the effect of electronic correlations on the electronic properties of both graphene and graphane. The size of band gap in graphane increases from 3.7 eV in LDA to 4.9 eV in GW approximation. By calculating maximally localized Wannier wave functions, we evaluate the necessary integrals to get the Hubbard U and the exchange J interaction from first principles for both graphene and graphane. Our ab-initio estimates indicate that in the case of graphene, in addition to the hopping amplitude t ∼ 2.8 eV giving rise to the Dirac nature of low lying excitations, the Hubbard U value...