Gate-tunable valley currents, non-local resistances and valley accumulation in bilayer graphene nanostructures

Abstract

Using the Büttiker-Landauer formulation of transport theory in the linear response regime, the valley currents and non-local resistances of bilayer graphene nanostructures with broken inversion symmetry are calculated. It is shown that broken inversion symmetry in bilayer graphene nanostructures leads to striking enhancement of the non-local 4-terminal resistance and to valley currents several times stronger than the conventional electric current when the Fermi energy is in the spectral gap close to the energy of Dirac point. The scaling relation between local and non-local resistances is investigated as the gate voltage varies at zero Fermi energy and a power-law is found to be satisfied. The valley velocity field and valley accumulation in four-terminal bilayer graphene nanostructures are evaluated in the presence of inversion symmetry breaking. The valley velocity and non-local resistance are found to scale differently with the applied gate voltage. The unit cell-averaged valley accumulation is found to exhibit a dipolar spatial distribution consistent with the accumulation arising from the valley currents. We define and calculate a {\em valley capacitance} that characterizes the valley accumulation response to voltages applied to the nanostructure's contacts.

arXiv comment9 pages, 4 figures

References in corpus (30)

• Electric Field Effect in Atomically Thin Carbon Films
• Universal Dynamic Conductivity and Quantized Visible Opacity of Suspended Graphene
• Thermal Properties of Graphene, Carbon Nanotubes and Nanostructured Carbon Materials
• Berry Phase Effects on Electronic Properties
• Valley contrasting physics in graphene: magnetic moment and topological transport
• Unconventional quantum Hall effect and Berry's phase of 2pi in bilayer graphene
• Valley filter and valley valve in graphene
• Photovoltaic Hall effect in graphene
• Dimensional crossover of thermal transport in few-layer graphene materials
• Detecting Topological Currents in Graphene Superlattices
• Graphene valley filter using a line defect
• Generation and detection of pure valley current by electrically induced Berry curvature in bilayer graphene
• Gate-tunable Topological Valley Transport in Bilayer Graphene
• Conductance quantization in mesoscopic graphene
• Nonlocal Charge Transport Mediated by Spin Diffusion in the Spin-Hall Effect Regime
• Generation of valley polarized current in bilayer graphene
• Valley separation in graphene by polarized light
• Transmission through a boundary between monolayer and bilayer graphene
• Valley filtering using electrostatic potentials in bilayer graphene
• Valley currents and non-local resistances of graphene nanostructures with broken inversion symmetry from the perspective of scattering theory
• Identification of the Molecule-Metal Bonding Geometries of Molecular Nanowires
• Theoretical Study of Spin-dependent Electron Transport in Atomic Fe Nanocontacts
• Mechanism of the enhanced conductance of a molecular junction under tensile stress
• Tight Binding Model of Mn12 Single Molecule Magnets: Electronic and Magnetic Structure and Transport Properties
• Berry's phase and the anomalous velocity of Bloch wavepackets
• Understanding the electroluminescence emitted by single molecules in scanning tunneling microscopy experiments
• Two-probe theory of scanning tunneling microscopy of single molecules: Zn(II)-etioporphyrin on alumina
• Resonance Patterns of an Antidot Cluster: From Classical to Quantum Ballistics
• Why Are Large Persistent Currents Observed in Small Gold Rings?
• Lateral spin injection and detection through electrodeposited Fe/GaAs contacts

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