Tunneling in graphene-topological insulator hybrid devices

Abstract

Hybrid graphene-topological insulator (TI) devices were fabricated using a mechanical transfer method and studied via electronic transport. Devices consisting of bilayer graphene (BLG) under the TI Bi${}_2$Se${}_3$ exhibit differential conductance characteristics which appear to be dominated by tunneling, roughly reproducing the Bi${}_2$Se${}_3$ density of states. Similar results were obtained for BLG on top of Bi${}_2$Se${}_3$, with 10-fold greater conductance consistent with a larger contact area due to better surface conformity. The devices further show evidence of inelastic phonon-assisted tunneling processes involving both Bi${}_2$Se${}_3$ and graphene phonons. These processes favor phonons which compensate for momentum mismatch between the TI $\Gamma$ and graphene $K,K^{\prime }$ points. Finally, the utility of these tunnel junctions is demonstrated on a density-tunable BLG device, where the charge-neutrality point is traced along the energy-density trajectory. This trajectory is used as a measure of the ground-state density of states.

References in corpus (11)

• The electronic properties of graphene
• Boron nitride substrates for high-quality graphene electronics
• Vertical Field Effect Transistor based on Graphene-WS2 Heterostructures for flexible and transparent electronics
• Asymmetry gap in the electronic band structure of bilayer graphene
• Transport measurements across a tunable potential barrier in graphene
• Giant Phonon-induced Conductance in Scanning Tunneling Spectroscopy of Gate-tunable Graphene
• Rapid Surface Oxidation as a Source of Surface Degradation Factor for Bi2Se3
• Momentum-Resolved Landau-Level Spectroscopy of Dirac Surface State in Bi2Se3
• Electronic Transport in Dual-gated Bilayer Graphene at Large Displacement Fields
• Electron-phonon Coupling on the Surface of the Topological Insulator Bi2Se3: Determined from Surface Phonon Dispersion Measurements
• Fingerprints of Inelastic Transport at the Surface of the Topological Insulator Bi2Se3: Role of Electron-Phonon Coupling

Cited by in corpus (14)

• Spin Proximity Effects in Graphene/Topological Insulator Heterostructures
• Giant Edelstein effect in Topological-Insulator--Graphene heterostructures
• A moiré superlattice on the surface of a topological insulator
• Local and Global Screening Properties of Graphene Revealed through Landau Level Spectroscopy
• Heterostructures of graphene and topological insulators Bi${}_2$Se${}_3$, Bi${}_2$Te${}_3$, and Sb${}_2$Te${}_3$
• Single and bilayer graphene on the topological insulator Bi${}_2$Se${}_3$: Electronic and spin-orbit properties from first principles
• Superconductivity in twisted Graphene $\mathrm{NbS}{\mathrm{e}}_2$ heterostructures
• Van der Waals heterostructures with spin-orbit coupling
• Twist-angle dependent proximity induced spin-orbit coupling in graphene/topological insulator heterostructures
• Evidence for topological proximity effect in graphene coupled to topological insulator
• Magic angle conditions for twisted 3D topological insulators
• High density carriers at a strongly coupled graphene-topological insulator interface
• Berry curvature-induced local spin polarisation in gated graphene/WTe${}_2$ heterostructures
• Transmission in graphene-topological insulator heterostructures