Short range Coulomb correlations render massive Dirac fermions massless

Abstract

Tight binding electrons on a honeycomb lattice are described by an effective Dirac theory at low energies. Lowering symmetry by an alternate ionic potential ($\Delta$) generates a single-particle gap in the spectrum. We employ the dynamical mean field theory (DMFT) technique, to study the effect of on-site electron correlation ($U$) on massive Dirac fermions. For a fixed mass parameter $\Delta$, we find that beyond a critical value $U_{c1}(\Delta )$ massive Dirac fermions become massless. Further increasing $U$ beyond $U_{c2}(\Delta )$, there will be another phase transition to the Mott insulating state. Therefore the competition between the single-particle gap parameter, $\Delta$, and the Hubbard $U$ restores the semi-metallic nature of the parent Hamiltonian. The width of the intermediate semi-metallic regime shrinks by increasing the ionic potential. However, at small values of $\Delta$, there is a wide interval of $U$ values for which the system remains semi-metal.

4 pages, 5 figures

References in corpus (13)

• The electronic properties of graphene
• Energy Band Gap Engineering of Graphene Nanoribbons
• Graphane: a two-dimensional hydrocarbon
• Strength of effective Coulomb interactions in graphene and graphite
• Interactions and phase transitions on graphene's honeycomb lattice
• Dynamical polarization, screening, and plasmons in gapped graphene
• Interacting Dirac Fermions on Honeycomb Lattice
• Metallic phase in the two-dimensional ionic Hubbard model
• Electronic phase transitions in the half-filled ionic Hubbard model
• Dynamical Mean Field Study of The Dirac Liquid
• Correlated Dirac Fermions on the Honeycomb Lattice studied within Cluster Dynamical Mean Field Theory
• Finite temperature semimetal-insulator transition on the honeycomb lattice
• Exact Diagonalization Study of 2D Hubbard Model on Honeycomb Lattice: Semi-metal-Insulator Transition

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• Phase transitions in the binary-alloy Hubbard model: insight from strong-coupling perturbation theory
• Collective excitations and the nature of Mott transition in undoped gapped graphene
• Effects of correlations on honeycomb lattice in ionic-Hubbard Model
• Generalization of Lieb-Wu wave function inspired by one-dimensional ionic Hubbard model
• Quantum Phase transition in the two dimensional ionic-Hubbard model
• Semiconductor of spinons: from Ising band insulator to orthogonal band insulator