Quantum-metric-enabled exciton condensate in double twisted bilayer graphene

Abstract

Flat-band systems are a promising platform for realizing exotic collective ground states with spontaneously broken symmetry because the electron-electron interactions dominate over the kinetic energy. A collective ground state of particular interest is the chased after exciton condensate (EC). However, in flat band systems other collective ground states can compete with an EC phase, and the conventional treatment of the effect of thermal and quantum fluctuations predicts the EC phase should be unstable. Here, using double twisted bilayer graphene (TBLG) heterostructures as an example, we show that for realistic interaction strengths the EC phase is favored with respect to other TBLG's phases -- orbital magnetism and superconductivity -- when the TBLGs have opposite doping, and that the quantum metric of the Bloch wave functions stabilizes the EC, reversing the conclusion that would be drawn from the conventional approach in which quantum metric contributions are neglected. Our results suggest that the quantum metric plays a critical role in determining the stability of exciton condensates in double layers formed by systems with flat-bands.

arXiv comment6 pages, 6 figures

References in corpus (52)

• Magic-angle graphene superlattices: a new platform for unconventional superconductivity
• Correlated Insulator Behaviour at Half-Filling in Magic Angle Graphene Superlattices
• Moire bands in twisted double-layer graphene
• Tuning superconductivity in twisted bilayer graphene
• Superconductors, Orbital Magnets, and Correlated States in Magic Angle Bilayer Graphene
• Graphene bilayer with a twist: electronic structure
• Moiré Excitons in Van der Waals Heterostructures
• Flat Bands in Slightly Twisted Bilayer Graphene
• Graphene Bilayers with a Twist
• Bose-Einstein Condensation of Excitons in Bilayer Electron Systems
• Spontaneous Inter-layer Coherence in Double-Layer Quantum-Hall Systems I: Charged Vortices and Kosterlitz-Thouless Phase Transitions
• Superfluidity in topologically nontrivial flat bands
• Evidence of high-temperature exciton condensation in 2D atomic double layers
• High-temperature superfluidity with indirect excitons in van der Waals heterostructures
• Theory of phonon-mediated superconductivity in twisted bilayer graphene
• Evidence for a Goldstone Mode in a Double Layer Quantum Hall System
• Moiré superlattice in a MoSe${}_2$/hBN/MoSe${}_2$ heterostructure: from coherent coupling of inter- and intra-layer excitons to correlated Mott-like states of electrons
• A mechanism for anomalous Hall ferromagnetism in twisted bilayer graphene
• Room-Temperature Superfluidity in Graphene Bilayers
• Ab-Initio Theory of Moiré Superlattice Bands in Layered Two-Dimensional Materials
• Quantum Ferromagnetism and Phase Transitions in Double-Layer Quantum Hall Systems
• Excitonic superfluid phase in Double Bilayer Graphene
• Band geometry, Berry curvature and superfluid weight
• Topology-Bounded Superfluid Weight In Twisted Bilayer Graphene
• Superfluid weight and Berezinskii-Kosterlitz-Thouless transition temperature of twisted bilayer graphene
• Pressure dependence of the magic twist angle in graphene superlattices
• High Temperature Superfluidity in Double Bilayer Graphene
• Geometric and conventional contribution to superfluid weight in twisted bilayer graphene
• Mean-field theory for superconductivity in twisted bilayer graphene
• Gate-Tuned Spontaneous Exciton Insulator in Double-Quantum Wells
• Excitonic condensation of massless fermions in graphene bilayers
• Electron screening and excitonic condensation in double-layer graphene systems
• Strongly enhanced tunneling at total charge neutrality in double bilayer graphene-WSe${}_2$ heterostructures
• Theory of interlayer tunneling in bi-layer quantum Hall ferromagnets
• Interplay of exciton condensation and quantum spin Hall effect in InAs/GaSb bilayers
• Interlayer fractional quantum Hall effect in a coupled graphene double-layer
• Exciton condensate in bilayer transition metal dichalcogenides: strong coupling regime
• Spin-twisted Optical Lattices: Tunable Flat Bands and Larkin-Ovchinnikov Superfluids
• Exciton band topology in spontaneous quantum anomalous Hall insulators: applications to twisted bilayer graphene
• Excitonic Superfluidity and Screening in Electron-Hole Bilayer Systems
• Exciton Transport and Andreev Reflection in a Bilayer Quantum Hall System
• Competition of electron-phonon mediated superconductivity and Stoner magnetism on a flat band
• Universal phase diagrams with superconducting domes for electronic flat bands
• Spatially-indirect Exciton Condensate Phases in Double Bilayer Graphene
• Interlayer Transport in Bilayer Quantum Hall Systems
• Designing three-dimensional flat bands in nodal-line semimetals
• Chiral superfluid states in hybrid graphene heterostructures
• Quantitative description of Josephson-like tunneling in ${\nu }_T=1$ quantum Hall bilayers
• Excitonic fractional quantum Hall hierarchy in Moiré heterostructures
• Confinement-deconfinement transition due to spontaneous symmetry breaking in quantum Hall bilayers
• Quantum Geometric Exciton Drift Velocity
• Strong interlayer charge transfer due to exciton condensation in an electrically-isolated GaAs quantum well bilayer

Cited by in corpus (25)

• Superfluidity and Quantum Geometry in Twisted Multilayer Systems
• Quantum metric nonlinear Hall effect in a topological antiferromagnetic heterostructure
• Quantum Metric and Correlated States in Two-dimensional Systems
• The Ginzburg-Landau theory of flat band superconductors with quantum metric
• Nontrivial quantum geometry of degenerate flat bands
• Quantum geometric effect on Fulde-Ferrell-Larkin-Ovchinnikov superconductivity
• "Quantum Geometric Nesting" and Solvable Model Flat-Band Systems
• Instantaneous response and quantum geometry of insulators
• Geometric Stiffness in Interlayer Exciton Condensates
• Quantum Metric in Step Response
• Universal suppression of superfluid weight by disorder independent of quantum geometry and band dispersion
• Photogalvanic response in multi-Weyl semimetals
• Beginnings of Exciton Condensation in Coronene Analog of Graphene Double Layer
• Quantum Geometry and the Hidden Scales in Materials
• Quantum Enhanced Josephson Junction Field-Effect Transistors for Logic Applications
• Geometric semimetals and their simulation in synthetic matter
• Superfluid stiffness bounds in time-reversal symmetric superconductors
• Generalized Peierls substitution for Wannier obstructions: response to disorder and interactions
• Unconventional excitonic insulators in two-dimensional topological materials
• Quantum metric driven transition between superfluid and incoherent fluid
• Topological fluctuating electron-hole Cooper pairs in graphene-GaAs heterostructures
• Topological hybrid electron-hole Cooper pairing
• Quantum Geometry Driven Finite-Momentum Exciton Fluctuations in Flat-Band Systems
• Third-harmonic generation in superconductors: Role of quantum geometry in the competition between Higgs mode and quasiparticles
• Distinct topological excitonic insulators characterized by quantum geometry