Graphene-based topological insulator with an intrinsic bulk band gap above room temperature

Abstract

Topological insulators (TIs) represent a new quantum state of matter characterized by robust gapless states inside the insulating bulk gap. The metallic edge states of a two-dimensional (2D) TI, known as quantum spin Hall (QSH) effect, are immune to backscattering and carry fully spin-polarized dissipationless currents. However, existing 2D TIs realized in HgTe and InAs/GaSb suffer from small bulk gaps (<10 meV) well below room temperature, thus limiting their application in electronic and spintronic devices. Here, we report a new 2D TI comprising a graphene layer sandwiched between two Bi2Se3 slabs that exhibits a large intrinsic bulk band gap of 30 to 50 meV, making it viable for room-temperature applications. Distinct from previous strategies for enhancing the intrinsic spin-orbit coupling effect of the graphene lattice, the present graphene-based TI operates on a new mechanism of strong inversion between graphene Dirac bands and Bi2Se3 conduction bands. Strain engineering leads to effective control and substantial enhancement of the bulk gap. Recently reported synthesis of smooth graphene/Bi2Se3 interfaces demonstrates feasibility of experimental realization of this new 2D TI structure, which holds great promise for nanoscale device applications.

3 figures, 1 table

References in corpus (10)

• Van der Waals heterostructures
• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Topological Insulators with Inversion Symmetry
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Spin-orbit gap of graphene: First-principles calculations
• Nonlocal edge state transport in the quantum spin Hall state
• Quantum Spin Hall Effect in Inverted Type II Semiconductors
• Observation of Quantum Spin Hall States in InAs/GaSb Bilayers under Broken Time-Reversal Symmetry
• Photoemission induced gating of topological insulator

Cited by in corpus (32)

• Colloquium: Topological Band Theory
• Dirac materials
• Topological Phases in Two-Dimensional Materials: A Brief Review
• New Family of Quantum Spin Hall Insulators in Two-dimensional Transition-Metal Halide with Large Nontrivial Band Gaps
• New Family of Robust 2D Topological Insulators in van der Waals Heterostructures
• Characterization of Thin Film Materials using SCAN meta-GGA, an Accurate Nonempirical Density Functional
• Signature of large-gap quantum spin Hall state in the layered mineral jacutingaite
• New Families of Large Band Gap 2D Topological Insulators in Ethynyl-Derivative Functionalized Compounds
• Multiple Quantum Phases in Graphene with Enhanced Spin-Orbit Coupling: From the Quantum Spin Hall Regime to the Spin Hall Effect and a Robust Metallic State
• ${\mathbb{Z}}_2$ invariance of Germanene on MoS${}_2$ from first principles
• Gate-Tunable Tunneling Resistance in Graphene/Topological Insulator Vertical Junctions
• Heterostructures of graphene and topological insulators Bi${}_2$Se${}_3$, Bi${}_2$Te${}_3$, and Sb${}_2$Te${}_3$
• Robust Room-Temperature Quantum Spin Hall Effect in Methyl-functionalized InBi honeycomb film
• Superconductivity in twisted Graphene $\mathrm{NbS}{\mathrm{e}}_2$ heterostructures
• Tunneling in graphene-topological insulator hybrid devices
• Proximity induced topological state in graphene
• Evidence for topological proximity effect in graphene coupled to topological insulator
• Gallium Bismuth Halides GaBi-X2 (X= I, Br, Cl) Monolayers with Distorted Hexagonal Framework: Novel Room-Temperature Quantum Spin Hall Insulators
• Opening Band Gap without Breaking Lattice Symmetry: A New Route toward Robust Graphene-Based Nanoelectronics
• High density carriers at a strongly coupled graphene-topological insulator interface
• Quantum phase transitions of topological insulators without gap closing
• Interaction effects in non-equilibrium transport properties of a four-terminal topological corner junction
• Topological matter: graphene and superfluid 3He
• Edge states, spin transport and impurity induced local density of states in spin-orbit coupled graphene
• Electron dynamics in graphene with spin-orbit couplings and periodic potentials
• Floquet topological phases on a honeycomb lattice using elliptically polarized light
• An anomalous band inversion protected by symmetry in a topological insulator of the Kane-Mele model
• Photoprotected spin Hall effect on graphene with substrate induced Rashba spin-orbit coupling
• Spin-charge coupled transport in van der Waals systems with random tunneling
• Thermopower generation and thermoelectric cooling in a Kane-Mele normal-insulator-superconductor nano-junction
• Dynamic dielectric function and phonon self-energy from electrons strongly correlated with acoustic phonons in 2D Dirac crystals
• Controllable magnetic correlation between two impurities by spin-orbit coupling in graphene