Determining spin-orbit coupling in graphene by quasiparticle interference imaging

Abstract

Inducing and controlling spin-orbit coupling (SOC) in graphene is key to create topological states of matter, and for the realization of spintronic devices. Placing graphene onto a transition metal dichalcogenide is currently the most successful strategy to achieve this goal, but there is no consensus as to the nature and the magnitude of the induced SOC. Here, we show that the presence of backscattering in graphene-on-WSe${}_2$ heterostructures can be used to probe SOC and to determine its strength quantitatively, by imaging quasiparticle interference with a scanning tunneling microscope. A detailed theoretical analysis of the Fourier transform of quasiparticle interference images reveals that the induced SOC consists of a valley-Zeeman (${\lambda }_{\text{vZ}}\approx 2$ meV) and a Rashba (${\lambda }_{\text{R}}\approx 15$ meV) term, one order of magnitude larger than what theory predicts, but in excellent agreement with earlier transport experiments. The validity of our analysis is confirmed by measurements on a 30 degree twist angle heterostructure that exhibits no backscattering, as expected from symmetry considerations. Our results demonstrate a viable strategy to determine SOC quantitatively by imaging quasiparticle interference.

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Cited by in corpus (23)

• Twist-angle tunable spin texture in WSe${}_2$/graphene van der Waals heterostructures
• Correlated Phases in Spin-Orbit-Coupled Rhombohedral Trilayer Graphene
• Spin-orbit proximity in MoS${}_2$/bilayer graphene heterostructures
• Symmetry-broken metallic orders in spin-orbit-coupled Bernal bilayer graphene
• Topological flat bands, valley polarization, and interband superconductivity in magic-angle twisted bilayer graphene with proximitized spin-orbit couplings
• Spintronics in 2D graphene-based van der Waals heterostructures
• Spin Hall Effect: Symmetry Breaking, Twisting, and Giant Disorder Renormalization
• Engineering two-dimensional kagome topological insulator from porous graphene
• Electron Interactions in Rashba Materials
• Designing Topological High-Order Van Hove Singularities: Twisted Bilayer Kagomé
• Landau-level spectrum and the effect of spin-orbit coupling in monolayer graphene on transition metal dichalcogenides
• Designer spin-orbit superlattices: symmetry-protected Dirac cones and spin Berry curvature in two-dimensional van der Waals metamaterials
• Dirac-Rashba fermions and quantum valley Hall insulators in graphene-based 2D heterostructures
• Probing moiré electronic structures through quasiparticle interference
• Angular dependence of the interlayer coupling at the interface between two dimensional materials 1T-PtSe${}_2$ and graphene
• Entanglement harvesting in buckled honeycomb lattices by vacuum fluctuations in a microcavity
• Topological phases, van Hove singularities, and spin texture in magic-angle twisted bilayer graphene in the presence of proximity-induced spin-orbit couplings
• Increasing the proximity induced spin-orbit coupling in bilayer graphene/WSe${}_2$ heterostructures with pressure
• Interplay of Rashba and valley-Zeeman splittings in weak localization of spin-orbit coupled graphene
• Impact of spin-orbit coupling on electron correlation corrections to the density of states in anisotropic conductors
• Effects of spin-orbit coupling in a valley chiral kagomé network
• Delusive chirality and periodic strain pattern in moiré systems
• Revealing the impact of ambient molecular contamination on scanning tunneling microscopy and spectroscopy of layered materials