45 research outputs found
Transmission and Goos-H\"anchen like Shifts through a Graphene Double Barrier in an Inhomogeneous Magnetic Field
We studied the transport properties of electrons in graphene as they are
scattered by a double barrier potential in the presence of an inhomogeneous
magnetic field. We computed the transmission coefficient and Goos-H\"anchen
like shifts for our system and noticed that transmission is not allowed for
certain range of energies. In particular, we found that, in contrast to the
electrostatic barriers, the magnetic barriers are able to confine Dirac
fermions. We also established some correlation between the electronic
transmission properties of Dirac fermions with the Goos-H\"anchen like shifts,
as reflected in the numerical data.Comment: 18 pages, 6 figure
Confined Dirac Particles in Constant and Tilted Magnetic Field
We study the confinement of charged Dirac particles in 3+1 space-time due to
the presence of a constant and tilted magnetic field. We focus on the nature of
the solutions of the Dirac equation and on how they depend on the choice of
vector potential that gives rise to the magnetic field. In particular, we
select a "Landau gauge" such that the momentum is conserved along the direction
of the vector potential yielding spinor wavefunctions, which are localized in
the plane containing the magnetic field and normal to the vector potential.
These wave functions are expressed in terms of the Hermite polynomials. We
point out the relevance of these findings to the relativistic quantum Hall
effect and compare with the results obtained for a constant magnetic field
normal to the plane in 2+1 dimensions.Comment: 10 page
Tunneling of Massive Dirac Fermions in Graphene through Time-periodic Potential
The energy spectrum of graphene sheet with a single barrier structure having
a time periodic oscillating height and subjected to magnetic field is analyzed.
The corresponding transmission is studied as function of the obtained energy
and the potential parameters. Quantum interference within the oscillating
barrier has an important effect on quasiparticles tunneling. In particular the
time-periodic electromagnetic field generates additional sidebands at energies
\epsilon + l\hbar \omega (l=0,\pm 1, \cdots) in the transmission probability
originating from the photon absorption or emission within the oscillating
barrier. Due to numerical difficulties in truncating the resulting coupled
channel equations we limited ourselves to low quantum channels, i.e. l=0,\pm 1.Comment: 20 pages, 13 figures, references added. Version to appear in EPJ