Orbital Hall effect as an alternative to valley Hall effect in gapped graphene

Abstract

Gapped graphene has been proposed to be a good platform to observe the valley Hall effect, a transport phenomenon involving the flow of electrons that are characterized by different valley indices. In the present work, we show that this phenomenon is better described as an instance of the orbital Hall effect, where the ambiguous "valley" indices are replaced by a physical quantity, the orbital magnetic moment, which can be defined uniformly over the entire Brillouin zone. This description removes the arbitrariness in the choice of arbitrary cut-off for the valley-restricted integrals in the valley Hall conductivity, as the conductivity in the orbital Hall effect is now defined as the Brillouin zone integral of a new quantity, called the orbital Berry curvature. This reformulation in terms of OHE provides the direct explanation to the accumulated opposite orbital moments at the edges of the sample, observed in previous Kerr rotation measurements.

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Cited by in corpus (68)

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• Phase diagrams and edge-state transitions in graphene with spin-orbit coupling and magnetic and pseudomagnetic fields
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• Strain-induced topological phase transition at (111) SrTiO${}_3$-based heterostructures
• Tunneling valley Hall effect induced by coherent geometric phase
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• Non-reciprocity in magnon mediated charge-spin-orbital current interconversion
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• Orbital Hall effect and topology on a two-dimensional triangular lattice: from bulk to edge
• Optical properties, plasmons, and orbital Skyrme textures in twisted TMDs
• Valley-dependent giant orbital moments and transport feature in rhombohedral graphene multilayers
• Orbital Magnetization under an Electric Field and Orbital Magnetoelectric Polarizabilty for a Bilayer Chern System
• Topological switching in bilayer magnons via electrical control
• First-order effect of electron-electron interactions on the anomalous Hall conductivity of massive Dirac fermions
• Orbital Hall Conductivity in a Graphene/Haldane and Haldane/Haldane Bilayers
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• Comparing the Extrinsic Orbital Hall Effect in Centrosymmetric and Noncentrosymmetric Systems: Insights from Bilayer Transition Metal Dichalcogenides
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• Ferroelectric Switchable Topological Magnon Hall Effect in Type-I Multiferroics
• Semiclassical theory for the orbital magnetic moment of superconducting quasiparticles
• Orbital Dynamics in Centrosymmetric Systems
• Orbital Longitudinal Magneto-electric Coupling in Multilayer Graphene
• Orbital torques and orbital pumping in two-dimensional rare-earth dichalcogenides
• Relativistic Spin-Lattice Interaction Compatible with Discrete Translation Symmetry in Solids
• Orbital Hall effect in spin-3/2 hole-doped semiconductors and its implications for orbitronics
• Electric spin and valley Hall effects