Vestigial singlet pairing in a fluctuating magnetic triplet superconductor: Applications to graphene moiré systems

Abstract

Motivated by the phenomenology of graphene moiré superlattices, we study a 2D model with strong tendencies towards both magnetism and triplet superconductivity. Individually, their respective order parameters, $\vec{N}$ and $\vec{d}$, cannot order at finite temperature. Nonetheless, the model exhibits a variety of vestigial phases, including charge-$4e$ superconductivity and broken time-reversal symmetry. Our main focus is on a phase characterized by finite $\vec{d}\cdot \vec{N}$, which has the same symmetries as the BCS state, a Meissner effect, and metastable supercurrents, yet rather different spectral properties: most notably, the suppression of the electronic density of states at the Fermi can resemble that of either a fully gapped or nodal superconductor, depending on parameters. This could provide a possible explanation for recent tunneling experiments in graphene moiré systems.

20 pages, 8 figures

References in corpus (26)

• Theory of Intertwined Orders in High Temperature Superconductors
• Tunable Phase Boundaries and Ultra-Strong Coupling Superconductivity in Mirror Symmetric Magic-Angle Trilayer Graphene
• Electric field tunable unconventional superconductivity in alternating twist magic-angle trilayer graphene
• Evidence for unconventional superconductivity in twisted bilayer graphene
• Zero-field superconducting diode effect in small-twist-angle trilayer graphene
• Charge $4e$ superconductivity from pair density wave order in certain high temperature superconductors
• Theory of zero-field superconducting diode effect in twisted trilayer graphene
• Chern Fermi pocket, topological pair density wave, and charge-4e and charge-6e superconductivity in kagome superconductors
• Quartic metal: Spontaneous breaking of time-reversal symmetry due to four-fermion correlations in Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$
• Topological charge density waves at half-integer filling of a moiré superlattice
• Pairing symmetry of twisted bilayer graphene: a phenomenological synthesis
• Charge-$4e$ superconductivity from nematic superconductors in 2D and 3D
• Spontaneous time-reversal symmetry breaking in twisted double bilayer graphene
• Stabilizing fluctuating spin-triplet superconductivity in graphene via induced spin-orbit coupling
• Nodal band-off-diagonal superconductivity in twisted graphene superlattices
• Electron spin resonance and collective excitations in magic-angle twisted bilayer graphene
• Phase coherence of pairs of Cooper pairs as quasi-long-range order of half-vortex pairs in a two-dimensional bilayer system
• Prediction of time-reversal-symmetry breaking fermionic quadrupling condensate in twisted bilayer graphene
• Solvable model for a charge-$4e$ superconductor
• Andreev Reflection in Scanning Tunneling Spectroscopy of Unconventional Superconductors
• Junctions and superconducting symmetry in twisted bilayer graphene
• Symmetry-broken Chern insulators in twisted double bilayer graphene
• Unconventional superconductivity with preformed pairs in twisted bilayer graphene
• Effective model and Magnetic Properties of the Resistive Electron Quadrupling State
• A new flavor of correlation and superconductivity in small twist-angle trilayer graphene
• Berezinskii-Kosterlitz-Thouless transition transport in spin-triplet superconductor

Cited by in corpus (8)

• Nodal band-off-diagonal superconductivity in twisted graphene superlattices
• Nematic Superconductivity and Its Critical Vestigial Phases in the Quasi-crystal
• Approximate symmetries, insulators, and superconductivity in continuum-model description of twisted WSe${}_2$
• Eliashberg Theory and Superfluid Stiffness of Band-Off-Diagonal Pairing in Twisted Graphene
• Probing superconductivity with tunneling spectroscopy in rhombohedral graphene
• Local condensation of charge-$4e$ superconductivity at a nematic domain wall
• Vestigial $d$-wave charge-$4e$ Superconductivity from Bidirectional Pair Density Waves
• Superconducting States and Intertwined Orders in Metallic Altermagnets