Tunable valley Hall effect in gate-defined graphene superlattices

Abstract

We theoretically investigate gate-defined graphene superlattices with broken inversion symmetry as a platform for realizing tunable valley dependent transport. Our analysis is motivated by recent experiments [C. Forsythe et al., Nat. Nanotechnol. 13, 566 (2018)] wherein gate-tunable superlattice potentials have been induced on graphene by nanostructuring a dielectric in the graphene/patterneddielectric/gate structure. We demonstrate how the electronic tight-binding structure of the superlattice system resembles a gapped Dirac model with associated valley dependent transport using an unfolding procedure. In this manner we obtain the valley Hall conductivities from the Berry curvature distribution in the superlattice Brillouin zone, and demonstrate the tunability of this conductivity by the superlattice potential. Finally, we calculate the valley Hall angle relating the transverse valley current and longitudinal charge current and demonstrate the robustness of the valley currents against irregularities in the patterned dielectric.

arXiv comment12 pages, 11 figures

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Cited by in corpus (9)

• Orbital Hall effect as an alternative to valley Hall effect in gapped graphene
• Semiclassical equations of motion for disordered conductors: extrinsic interband velocity, corrected collision integral and spin-orbit torques
• Spontaneous Valley Spirals in Magnetically Encapsulated Twisted Bilayer Graphene
• Quantum kinetic theory of quadratic responses
• Understanding Disorder in Monolayer Graphene Devices with Gate-Defined Superlattices
• Valley current filtering and reversal by parallel side contacted armchair nanotubes
• Origins of Valley Current Reversal in Partially Overlapped Graphene Layers
• Energy symmetry and interlayer wave function ratio of tunneling electrons in partially overlapped graphene
• Tunnel Valley Current Filter in the Partially Overlapped Graphene under the Vertical Electric Field