Pseudospin Paramagnons and the Superconducting Dome in Magic Angle Twisted Bilayer Graphene

Abstract

We present a theory of superconductivity in twisted bilayer graphene in which attraction is generated between electrons on the same honeycomb sublattice when the system is close to a sublattice polarization instability. The resulting Cooper pairs are spin-polarized valley-singlets. Because the sublattice polarizability is mainly contributed by interband fluctuations, superconductivity occurs over a wide range of filling fraction. It is suppressed by i) applying a sublattice polarizing field (generated by an aligned BN substrate) or ii) changing moiré band filling to favor valley polarization. The enhanced intrasublattice attraction close to sublattice polarization instability is analogous to enhanced like-spin attraction in liquid ${}^3$He near the melting curve and the enhanced valley-singlet repulsion close to valley-polarization instabilities is analogous to enhanced spin-singlet repulsion in metals that are close to a ferromagnetic instability. We comment on the relationship between our pseudospin paramagnon model and the rich phenomenology of superconductivity in twisted bilayer and multilayer graphene.

arXiv commentmaintext 5 pages, 3 figures

References in corpus (29)

• Magic-angle graphene superlattices: a new platform for unconventional superconductivity
• Tuning superconductivity in twisted bilayer graphene
• Emergent ferromagnetism near three-quarters filling in twisted bilayer graphene
• Superconductors, Orbital Magnets, and Correlated States in Magic Angle Bilayer Graphene
• Intrinsic quantized anomalous Hall effect in a moiré heterostructure
• Tunable Phase Boundaries and Ultra-Strong Coupling Superconductivity in Mirror Symmetric Magic-Angle Trilayer Graphene
• Strange metal in magic-angle graphene with near Planckian dissipation
• Untying the insulating and superconducting orders in magic-angle graphene
• Theory of phonon-mediated superconductivity in twisted bilayer graphene
• Cascade of electronic transitions in magic-angle twisted bilayer graphene
• Cascade of Phase Transitions and Dirac Revivals in Magic Angle Graphene
• Decoupling superconductivity and correlated insulators in twisted bilayer graphene
• Superconductivity in rhombohedral trilayer graphene
• Isospin magnetism and spin-triplet superconductivity in Bernal bilayer graphene
• Phonon scattering dominated electron transport in twisted bilayer graphene
• Superconductivity without insulating states in twisted bilayer graphene stabilized by monolayer WSe${}_2$
• Transport Spectroscopy of Symmetry-Broken Insulating States in Bilayer Graphene
• Electrostatic effects, band distortions and superconductivity in twisted graphene bilayers
• Quantized Transport in Graphene p-n Junctions in Magnetic Field
• Tuning electron correlation in magic-angle twisted bilayer graphene using Coulomb screening
• Competing zero-field Chern insulators in Superconducting Twisted Bilayer Graphene
• Strong electron-phonon coupling, electron-hole asymmetry, and nonadiabaticity in magic-angle twisted bilayer graphene
• Electronic band structure and pinning of Fermi energy to van Hove singularities in twisted bilayer graphene: a self consistent approach
• Gate-Defined Josephson Junctions in Magic-Angle Twisted Bilayer Graphene
• Coulomb interaction, phonons, and superconductivity in twisted bilayer graphene
• Pseudospin Order in Monolayer, Bilayer, and Double-Layer Graphene
• Weak-field Hall Resistivity and Spin/Valley Flavor Symmetry Breaking in Magic-Angle Twisted Bilayer Graphene
• Competition of electron-phonon mediated superconductivity and Stoner magnetism on a flat band
• Equation of state of two--dimensional ${}^3$He at zero temperature

Cited by in corpus (12)

• Superconductivity in Twisted Double Bilayer Graphene Stabilized by WSe${}_2$
• Spin and Orbital Metallic Magnetism in Rhombohedral Trilayer Graphene
• Dirac cone spectroscopy of strongly correlated phases in twisted trilayer graphene
• Nodal band-off-diagonal superconductivity in twisted graphene superlattices
• Electron spin resonance and collective excitations in magic-angle twisted bilayer graphene
• Pair Density Waves from Local Band Geometry
• Euler Obstructed Cooper Pairing in Twisted Bilayer Graphene: Nematic Nodal Superconductivity and Bounded Superfluid Weight
• Superconductivity from spin fluctuations and long-range interactions in magic-angle twisted bilayer graphene
• Competition of Exchange and Correlation Energies in Two-Dimensional $N$-component Electron Gas Ferromagnetism
• Spectroscopic signature of spin triplet odd-valley superconductivity in two-dimensional materials
• Mean-field Modelling of Moiré Materials: A User's Guide with Selected Applications to Twisted Bilayer Graphene
• Decomposing Electronic Structures in Twisted Multilayers: Bridging Spectra and Incommensurate Wave Functions