Excitonic condensation of massless fermions in graphene bilayers

Abstract

Graphene, a single sheet of graphite with honeycomb lattice structure, has massless carriers with tunable density and polarity. We investigate the ground state phase diagram of two graphene sheets (embedded in a dielectric) separated by distance $d$ where the top layer has electrons and the bottom layer has holes, using mean-field theory. We find that a uniform excitonic condensate occurs over a large range of carrier densities and is weakly dependent on the relative orientation of the two sheets. We obtain the excitonic gap, quasiparticle energy and the density of states. We show that both, the condensate phase stiffness and the mass of the excitons, with massless particles as constituents, vary as the square-root of the carrier density, and predict that the condensate will not undergo Wigner crystallization.

4 pages, 3 figures; substantial text revision

References in corpus (6)

• Quantized Transport in Graphene p-n Junctions in Magnetic Field
• Chirality and Correlations in Graphene
• Density dependent exchange contribution to $\partial \mu /\partial n$ in extrinsic graphene
• Spontaneous Symmetry Breaking and Quantum Hall Effect in Graphene
• Wigner supersolid of excitons in electron-hole bilayers
• Effect of electron-electron interaction on the Fermi surface topology of doped graphene

Cited by in corpus (27)

• Electron screening and excitonic condensation in double-layer graphene systems
• Cooper pairing of electrons and holes in graphene bilayer: Correlation effects
• Interaction-Enhanced Coherence Between Two-Dimensional Dirac Layers
• Exciton condensate in bilayer transition metal dichalcogenides: strong coupling regime
• Coulomb Drag and Magnetotransport in Graphene Double Layers
• Theory of Coulomb drag for massless Dirac fermions
• Vortices, zero modes and fractionalization in bilayer-graphene exciton condensate
• Coherence and Optical Emission from Bilayer Exciton Condensates
• Enhancement of electron-hole superfluidity in double few-layer graphene
• Influence of Disorder on Electron-Hole Pair Condensation in Graphene Bilayers
• AA-stacked bilayer graphene in an applied electric field: Tunable antiferromagnetism and coexisting exciton order parameter
• Gapped phase in AA stacked bilayer graphene
• Coulomb drag and counterflow Seebeck coefficient in bilayer-graphene double layers
• Density fluctuation effects on the exciton condensate in double layer graphene
• Excitonic gap formation and condensation in the bilayer graphene structure
• Excitonic condensation in spatially separated one-dimensional systems
• Photoemission spectra of massless Dirac fermions on the verge of exciton condensation
• Phases of the excitonic condensate in two-layer graphene
• Spectral properties of excitons in the bilayer graphene
• Holographic D3-probe-D5 Model of a Double Layer Dirac Semimetal
• Influence of topological excitations on Shapiro steps and microwave dynamical conductance in bilayer exciton condensates
• Zero modes of the generalized fermion-vortex system in magnetic field
• Prediction of the quantization of magnetic flux in double layer exciton superfluids
• Superfluidity of a rarefied gas of electron-hole pairs in a bilayer system
• Strong enhancement of third harmonic generation in a double layer graphene system caused by electron-hole pairing
• Excitonic gap generation in thin-film topological insulators
• Density of states in the bilayer graphene with the excitonic pairing interaction