Bulk and Edge Properties of Twisted Double-Bilayer Graphene
arXiv:2101.03621 · doi:10.1038/s41567-021-01419-5
Abstract
The emergence of controlled, two-dimensional moiré materials has uncovered a new platform for investigating topological physics. Twisted double bilayer graphene (TDBG) has been predicted to host a topologically non-trivial gapped phase with Chern number equal to two at charge neutrality, when half the flat bands are filled. However, it can be difficult to diagnose topological states using a single measurement because it is ideal to probe the bulk and edge properties at the same time. Here, we report a combination of chemical potential measurements, transport measurements, and theoretical calculations that show that twisted double bilayer graphene can host metallic edge transport while simultaneously being insulating in the bulk. A Landauer-Buttiker analysis of measurements on multi-terminal samples allows us to quantitatively assess edge state scattering. We interpret these results as signatures of the predicted topological phase at charge neutrality.
References in corpus (26)
- Magic-angle graphene superlattices: a new platform for unconventional superconductivity
- Quantum Spin Hall Insulator State in HgTe Quantum Wells
- Correlated Insulator Behaviour at Half-Filling in Magic Angle Graphene Superlattices
- Moire bands in twisted double-layer graphene
- Emergent ferromagnetism near three-quarters filling in twisted bilayer graphene
- Intrinsic quantized anomalous Hall effect in a moiré heterostructure
- Topological insulators in twisted transition metal dichalcogenide homobilayers
- Electric Field Tunable Correlated States and Magnetic Phase Transitions in Twisted Bilayer-Bilayer Graphene
- Spin-polarized Correlated Insulator and Superconductor in Twisted Double Bilayer Graphene
- Correlated states in twisted double bilayer graphene
- Electronic properties of graphene-based bilayer systems
- Strongly Correlated Chern Insulators in Magic-Angle Twisted Bilayer Graphene
- Exponential localization of Wannier functions in insulators
- Chern Insulators and Topological Flat-bands in Magic-angle Twisted Bilayer Graphene
- Correlated Insulating States in Twisted Double Bilayer Graphene
- Flavour Hund's Coupling, Correlated Chern Gaps, and Diffusivity in Moiré Flat Bands
- Tunable correlation-driven symmetry breaking in twisted double bilayer graphene
- Flatbands in twisted double bilayer graphene
- Band structure and topological property of twisted double bilayer graphenes
- Symmetry broken Chern insulators and magic series of Rashba-like Landau level crossings in magic angle bilayer graphene
- Chemical Potential and Quantum Hall Ferromagnetism in Bilayer Graphene
- Edge Transport in the Trivial Phase of InAs/GaSb
- Direct Measurement of the Fermi Energy in Graphene Using a Double Layer Structure
- Hofstadter Topology: Non-crystalline Topological Materials at High Flux
- Band topology and quantum spin Hall effect in bilayer graphene
- Bulk valley transport and Berry curvature spreading at the edge of flat bands
Cited by in corpus (16)
- Tunable moiré materials for probing Berry physics and topology
- Nonlinear anomalous Hall effects probe topological phase-transitions in twisted double bilayer graphene
- Spontaneous time-reversal symmetry breaking in twisted double bilayer graphene
- Observation of linear and nonlinear light localization at the edges of moiré lattices
- Signature of Correlated Insulator in Electric Field Controlled Superlattice
- Symmetry-broken Chern insulators in twisted double bilayer graphene
- Direct observation of moiré flat-band breakdown at the edge of magic-angle twisted bilayer graphene
- Quantum anomalous Hall crystals in moiré bands with higher Chern number
- Ferroelectricity in twisted double bilayer graphene
- Absence of Edge States in The Valley Chern Insulator in Moiré Graphene
- Quantum geometric moment encodes stacking order of moiré matter
- Independently Tunable Flat Bands and Correlations in a Graphene Double Moiré System
- Emergent Symmetry and Valley Chern Insulator in Twisted Double-Bilayer Graphene
- Second-Order Conductivity Probes a Cascade of Singularities in a Moiré Superlattice
- Shift current response in twisted double bilayer graphenes
- Second-Order Synaptic Memory using Inherent Plasticity of Moiré Superlattices