Effects of dynamical screening on the BCS-BEC crossover in double bilayer graphene: Density functional theory for exciton bilayers

Abstract

We derive a gap equation for bilayer excitonic systems based on density functional theory and benchmark our results against quantum Monte-Carlo simulations and recent experiments on double bilayer graphene. The gap equation has a mean-field form but includes a consistent treatment of dynamical screening. We show that the gap survives at much higher densities than previously thought from mean-field estimates which gives strong indications that the double-bilayer graphene systems at zero magnetic field can be used as model systems to investigate the BCS-BEC crossover. Furthermore, we show that Josephson-like transfer of pairs can be substantial for small band gaps and densities.

arXiv comment6 pages and 3 figures (main article), 16 pages and 2 figures (Supplemental)

References in corpus (22)

• Biased bilayer graphene: semiconductor with a gap tunable by electric field effect
• Gate-induced insulating state in bilayer graphene devices
• The electronic properties of bilayer graphene
• Ab Initio Theory of Gate Induced Gaps in Graphene Bilayers
• Ab-initio theory of superconductivity - I: Density functional formalism and approximate functionals
• Determination of the gate-tunable bandgap and tight-binding parameters in bilayer graphene using infrared spectroscopy
• Excitonic superfluid phase in Double Bilayer Graphene
• Quantum Hall Drag of Exciton Superfluid in Graphene
• High Temperature Superfluidity in Double Bilayer Graphene
• Excitonic condensation in a symmetric electron-hole bilayer
• Strongly enhanced tunneling at total charge neutrality in double bilayer graphene-WSe${}_2$ heterostructures
• Low-energy models for correlated materials: bandwidth renormalization from Coulombic screening
• Cooper pairing of electrons and holes in graphene bilayer: Correlation effects
• Interaction-Enhanced Coherence Between Two-Dimensional Dirac Layers
• Development of Density-Functional Theory for Plasmon-Assisted Superconducting State: Application to Lithium Under High Pressures
• Excitons and biexcitons in symmetric electron-hole bilayers
• Excitonic Superfluidity and Screening in Electron-Hole Bilayer Systems
• Evidence from quantum Monte Carlo of large gap superfluidity and BCS-BEC crossover in double electron-hole layers
• Enhancement of electron-hole superfluidity in double few-layer graphene
• Multicomponent electron-hole superfluidity and the BCS-BEC crossover in double bilayer graphene
• Ultrarelativistic electron-hole pairing in graphene bilayer
• Multicomponent screening and superfluidity in gapped electron-hole double bilayer graphene with realistic bands

Cited by in corpus (5)

• Eliashberg theory for dynamical screening in bilayer exciton condensation
• Excitonic insulators and superfluidity in 2D bilayers without external fields
• Effects of intra-layer correlations on electron-hole double-layer superfluidity
• Exciton Superfluidity in 2D Heterostructures from First Principles: The importance of material specific screening
• Beyond Random Phase Approximation in electron-hole bilayer superfluidity