Abstract
We perform a numerical simulation of the effects of an orthogonal magnetic field on charge transport and shot noise in an armchair graphene ribbon with a lattice of antidots. This study relies on our envelope-function based code, in which the presence of antidots is simulated through a nonzero mass term and the magnetic field is introduced with a proper choice of gauge for the vector potential. We observe that by increasing the magnetic field, the energy gap present with no magnetic field progressively disappears, together with features related to commensurability and quantum effects. In particular, we focus on the behavior for high values of the magnetic field: we notice that when it is sufficiently large, the effect of the antidots vanishes and shot noise disappears, as a consequence of the formation of edge states crawling along the boundaries of the structure without experiencing any interaction with the antidots.
Highlights
Graphene, a planar hexagonal lattice of carbon atoms, represents one of the currently most studied and promising materials [1,2,3,4,5]
We have added to our code for the k · p [14] simulation of armchair graphene ribbons the capability of treating the effect of antidots and of an orthogonal magnetic field
In order to obtain an aspect ratio among those commonly used in experiments and an overall size yielding a problem of manageable computational complexity, we have considered a 110 nm wide and 200 nm long armchair graphene ribbon containing a set of circular antidots, all with a radius of r = 5.41 nm and located in its central 100 nm long region
Summary
A planar hexagonal lattice of carbon atoms, represents one of the currently most studied and promising materials [1,2,3,4,5]. Since its envelope-function transport equation is formally equivalent to the relativistic Dirac equation [11,12,13,14], graphene exhibits relativistic effects at velocities much smaller than the velocity of light, such as Klein tunneling and Zitterbewegung [15,16,17,18]. It is characterized by peculiar electrical noise characteristics [19,20,21,22]. Its behavior in the presence of high magnetic fields is interesting [1,23,24,25], since it exhibits an “anomalous” quantum Hall effect, observable even at room temperature, with a spectrum of unevenly spaced Landau levels and a Landau level at zero energy
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