Dispersive Landau levels and valley currents in strained graphene nanoribbons

Abstract

We describe a simple setup generating pure valley currents -- valley transport without charge transport -- in strained graphene nanoribbons with zigzag edges. The crucial ingredient is a uniaxial strain pattern which couples to the low-energy Dirac electrons as a uniform pseudomagnetic field. Remarkably, the resulting pseudo-Landau levels are not flat but disperse linearly from the Dirac points, with an opposite slope in the two valleys. We show how this is a natural consequence of an inhomogeneous Fermi velocity arising in the low-energy theory describing the system, which maps to an exactly-solvable singular Sturm-Liouville problem. The velocity of the valley currents can be controlled by tuning the magnitude of strain and by applying bias voltages across the ribbon. Furthermore, applying an electric field along the ribbon leads to pumping of charge carriers between the two valleys, realizing a valley analog of the chiral anomaly in one spatial dimension. These effects produce unique signatures that can be observed experimentally by performing ordinary charge transport measurements and spectroscopy.

8 pages, 4 figures + Appendices. v2: Minor corrections and improvements, published version

References in corpus (19)

• The electronic properties of graphene
• The Chiral Magnetic Effect
• Valley filter and valley valve in graphene
• A tight-binding approach to uniaxial strain in graphene
• Valley Dependent Optoelectronics from Inversion Symmetry Breaking
• Topological response in Weyl semimetals and the chiral anomaly
• Detecting Topological Currents in Graphene Superlattices
• Graphene valley filter using a line defect
• Novel electric field effects on Landau levels in Graphene
• Symmetry-based approach to electron-phonon interactions in graphene
• Generation of pure bulk valley current in graphene
• Valley filter in strain engineered graphene
• Chiral anomaly from strain-induced gauge fields in Dirac and Weyl semimetals
• Graphene Nanobubbles as Valley Filters and Beamsplitters
• Inhomogeneous Weyl and Dirac semimetals: Transport in axial magnetic fields and Fermi arc surface states from pseudo Landau levels
• Nonlinear valley and spin currents from Fermi pocket anisotropy in 2D crystals
• Algebraic solution of a graphene layer in a transverse electric and perpendicular magnetic fields
• In-situ strain tuning in hBN-encapsulated graphene electronic devices
• The Haldane model under nonuniform strain

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• Phase diagrams and edge-state transitions in graphene with spin-orbit coupling and magnetic and pseudomagnetic fields
• Electronic transport in two-dimensional strained Dirac materials under multi-step Fermi velocity barrier: transfer matrix method for supersymmetric systems
• Reverse strain-induced snake states in graphene nanoribbons
• Analytic solution to pseudo-Landau levels in strongly bent graphene nanoribbons
• Unification of valley and anomalous Hall effects in a strained lattice
• Magnon Landau levels in the strained antiferromagnetic honeycomb nanoribbons
• On the propagation of Dirac fermions in graphene with the strain-induced inhomogeneous Fermi velocity
• Landau levels in curved space realized in strained graphene
• Quantum Monte Carlo study of honeycomb antiferromagnets under a triaxial strain
• Complex Landau levels and related transport properties in the strained zigzag graphene nanoribbons
• Time-dependent strain-tuning topological magnon phase transition
• Absence of edge states at armchair edges in inhomogeneously strained graphene under a pseudomagnetic field
• Pseudo Landau levels, negative strain resistivity, and enhanced thermopower in twisted graphene nanoribbons
• Modulation of Landau levels and de Haas-van Alphen oscillation in magnetized graphene by uniaxial tensile strain/ stress
• Pseudo-magnetic fields in square lattices
• Helical superconducting edge modes from pseudo-Landau levels in graphene
• Non-Hermitian reshaping of high-order Landau modes
• Coherent states for dispersive pseudo-Landau-levels in strained honeycomb lattices
• Transport in strained graphene: Interplay of Abelian and axial magnetic fields
• Quantized valley Hall response from local bulk density variations
• Scalable tight-binding model for strained graphene