2007/01/05 by M. W. C. Dharma‐wardana, M. W. C. Dharma-wardana · 2 citations
Materials Science · Physics and Astronomy · #Graphene research and applications #Quantum and electron transport phenomena #Topological Materials and Phenomena #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.75.075427
published as Phys. Rev. B 75 075427 (2007) · ~7 pages, 6 figures
arxiv created 2007/01/05 · openalex publication_date 2007/02/28 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
First-principles density-functional calculations for graphene and defective graphene are used to examine when the quasi-two-dimensional electrons near the Fermi energy in graphene could be represented by massless fermions obeying a Dirac-Weyl (DW) equation. The DW model is found to be inapplicable to defective graphene containing even \ensuremath∼3% vacancies or N substitution. However, the DW model holds in the presence of weakly adsorbed molecular layers. The possibility of spin-polarized phases (SPP) of DW-massless fermions in pure graphene is considered. The exchange energy is evaluated from the analytic pair-distribution functions as well as in k space. The kinetic energy enhancement of the sipn-polarized phase nearly cancels the exchange enhancement, and the correlation energy plays a dominant residual role. The correlation energies are estimated via a model four-component two-dimensional electron fluid whose Coulomb coupling matches that of graphene. While SPPs appear with exchange only, the inclusion of correlations suppresses them in ideal graphene.