72 research outputs found
Disorder and Electronic Transport in Graphene
In this review, we provide an account of the recent progress in understanding
electronic transport in disordered graphene systems. Starting from a
theoretical description that emphasizes the role played by band structure
properties and lattice symmetries, we describe the nature of disorder in these
systems and its relation to transport properties. While the focus is primarily
on theoretical and conceptual aspects, connections to experiments are also
included. Issues such as short versus long-range disorder, localization (strong
and weak), the carrier density dependence of the conductivity, and conductance
fluctuations are considered and some open problems are pointed out.Comment: 18 pages, 5 figures, Topical Revie
Graphene n-p junction in a strong magnetic field: a semiclassical study
We provide a semiclassical description of the electronic transport through
graphene n-p junctions in the quantum Hall regime. A semiclassical
approximation for the conductance is derived in terms of the various snake-like
trajectories at the interface of the junction. For a symmetric (ambipolar)
configuration, the general result can be recovered by means of a simple
scattering approach, providing a very transparent qualitative description of
the problem under study. Consequences of our findings for the understanding of
recent experiments are discussed.Comment: 10 pages, 2 figure
The recursive Green's function method for graphene
We describe how to apply the recursive Green's function method to the
computation of electronic transport properties of graphene sheets and
nanoribbons in the linear response regime. This method allows for an amenable
inclusion of several disorder mechanisms at the microscopic level, as well as
inhomogeneous gating, finite temperature, and, to some extend, dephasing. We
present algorithms for computing the conductance, density of states, and
current densities for armchair and zigzag atomic edge alignments. Several
numerical results are presented to illustrate the usefulness of the method.Comment: 26 pages, 15 figures; submitted to Journal of Computational
Electronics (special issue on graphene
Semiclassical magnetotransport in graphene n-p junctions
We provide a semiclassical description of the electronic transport through
graphene n-p junctions in the quantum Hall regime. This framework is known to
experimentally exhibit conductance plateaus whose origin is still not fully
understood. In the magnetic regime (E < vF B), we show the conductance of
excited states is essentially zero, while that of the ground state depends on
the boundary conditions considered at the edge of the sample. In the electric
regime (E > vF B), for a step-like electrostatic potential (abrupt on the scale
of the magnetic length), we derive a semiclassical approximation for the
conductance in terms of the various snake-like trajectories at the interface of
the junction. For a symmetric configuration, the general result can be
recovered using a simple scattering approach, providing a transparent analysis
of the problem under study. We thoroughly discuss the semiclassical predicted
behavior for the conductance and conclude that any approach using fully
phase-coherent electrons will hardly account for the experimentally observed
plateaus.Comment: 22 pages, 19 figure
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