Interaction-driven (quasi-) insulating ground states of gapped electron-doped bilayer graphene

Abstract

Bernal bilayer graphene has recently been discovered to exhibit a wide range of unique ordered phases resulting from interaction-driven effects and encompassing spin and valley magnetism, correlated insulators, correlated metals, and superconductivity. This letter reports on a novel family of correlated phases characterized by spin and valley ordering, observed in electron-doped bilayer graphene. The novel correlated phases demonstrate an intriguing non-linear current-bias behavior at ultralow currents that is sensitive to the onset of the phases and is accompanied by an insulating temperature dependence, providing strong evidence for the presence of unconventional charge carrying degrees of freedom originating from ordering. These characteristics cannot be solely attributed to any of the previously reported phases, and are qualitatively different from the behavior seen previously on the hole-doped side. Instead, our observations align with the presence of charge- or spin-density-waves state that open a gap on a portion of the Fermi surface or fully gapped Wigner crystals. The resulting new phases, quasi-insulators in which part of the Fermi surface remains intact or valley-polarized and valley-unpolarized Wigner crystals, coexist with previously known Stoner phases, resulting in an exceptionally intricate phase diagram.

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Cited by in corpus (10)

• Symmetry-broken metallic orders in spin-orbit-coupled Bernal bilayer graphene
• Effective perpendicular electric field as a probe for interlayer pairing in ambient-pressure superconducting La${}_{2.85}$Pr${}_{0.15}$Ni${}_2$O${}_7$ thin films
• Switching spin filling sequence in a bilayer graphene quantum dot through trigonal warping
• Valley polarization, magnetization, and superconductivity in bilayer graphene near the van Hove singularity
• Fluctuating magnetism and Pomeranchuk effect in multilayer graphene
• Supercell Wannier functions and a faithful low-energy model for Bernal bilayer graphene
• Chiral Wigner crystal phases induced by Berry curvature
• Berry Phase Dynamics of Sliding Electron Crystals
• Mean-field analysis of a Hubbard interaction on Bernal Bilayer Graphene
• Full, three-quarter, half and quarter Wigner crystals in Bernal bilayer graphene