Spatial Current Patterns, Dephasing and Current Imaging in Graphene Nanoribbons
arXiv:1402.1502 · doi:10.1088/1367-2630/16/1/013054
Abstract
Using the non-equilibrium Keldysh Green's function formalism, we investigate the local, non-equilibrium charge transport in graphene nanoribbons (GNRs). In particular, we demonstrate that the spatial current patterns associated with discrete transmission resonances sensitively depend on the GNRs' geometry, size, and aspect ratio, the location and number of leads, and the presence of dephasing. We identify a relation between the spatial form of the current patterns, and the number of degenerate energy states participating in the charge transport. Furthermore, we demonstrate a principle of superposition for the conductance and spatial current patterns in multiple-lead configurations. We demonstrate that scanning tunneling microscopy (STM) can be employed to image spatial current paths in GNR with atomic resolution, providing important insight into the form of local charge transport. Finally, we investigate the effects of dephasing on the spatial current patterns, and show that with decreasing dephasing time, the current patterns evolve smoothly from those of a ballistic quantum network to those of classical resistor network.
25 pages, 12 figures
References in corpus (22)
- The electronic properties of graphene
- Ultrahigh electron mobility in suspended graphene
- Energy Band Gap Engineering of Graphene Nanoribbons
- Suspended Graphene: a bridge to the Dirac point
- Graphene Nano-Ribbon Electronics
- Molecular Transport Junctions: Vibrational Effects
- Role of Symmetry in the Transport Properties of Graphene Nanoribbons under Bias
- DNA nucleotide-specific modulation of μA transverse edge currents through a metallic graphene nanoribbon with a nanopore
- Electronic transport properties of graphene nanoribbons
- Coherent transport in graphene nanoconstrictions
- Imaging Magnetic Focusing of Coherent Electron Waves
- Unexpected features of branched flow through high-mobility two-dimensional electron gases
- Electronic transport through bilayer graphene flakes
- Spatial distribution of local currents of massless Dirac fermions in quantum transport through graphene nanoribbons
- On the imaging of electron transport in semiconductor quantum structures by scanning-gate microscopy: successes and limitations
- Imaging and controlling electron transport inside a quantum ring
- Imaging Electron Wave Functions Inside Open Quantum Rings
- Imaging Coulomb Islands in a Quantum Hall Interferometer
- Spectrum of -electrons in Graphene As a Macromolecule
- Spectrum of Electrons in Graphene as an Alternant Macromolecule and Its Specific Features in Quantum Conductance
- Electron transport through honeycomb lattice ribbons with armchair edges
- Atomic Resolution Imaging of Currents in Nanoscopic Quantum Networks via Scanning Tunneling Microscopy