DIRAC EQUATION FOR QUASI-PARTICLES IN GRAPHENE AND QUANTUM FIELD THEORY OF THEIR COULOMB INTERACTION

Abstract

There is evidence for existence of massless Dirac quasiparticles in graphene, which satisfy Dirac equation in (1+2) dimensions near the so called Dirac points which lie at the corners at the graphene's brilluoin zone. We revisit the derivation of Dirac equation in (1+2) dimensions obeyed by quasiparticles in graphene near the Dirac points. It is shown that parity operator in (1+2) dimensions play an interesting role and can be used for defining "conserved" currents resulting from the underlying Lagrangian for Dirac quasiparticles in graphene which is shown to have UA(1) × UB(1) symmetry. Further the quantum field theory (QFT) of Coulomb interaction of 2D graphene is developed and applied to vacuum polarization and electron self-energy and the renormalization of the effective coupling g of this interaction and Fermi velocity vf which has important implications in the renormalization group analysis of g and vf.