4 research outputs found
Topological features of hydrogenated graphene
Hydrogen adatoms are one of the most the promising proposals for the
functionalization of graphene. Hydrogen induces narrow resonances near the
Dirac energy, which lead to the formation of magnetic moments. Furthermore,
they also create local lattice distortions which enhance the spin-orbit
coupling. The combination of magnetism and spin-orbit coupling allows for a
rich variety of phases, some of which have non trivial topological features. We
analyze the interplay between magnetism and spin-orbit coupling in ordered
arrays of hydrogen on graphene monolayers, and classify the different phases
that may arise. We extend our model to consider arrays of adsorbates in
graphene-like crystals with stronger intrinsic spin-orbit couplings.Comment: 6 pages, 4 figure
Tunneling and transmission resonances of a Dirac particle by a double barrier
We calculate the tunneling process of a Dirac particle across two square
barriers separated a distance , as well as the scattering by a double cusp
barrier where the centers of the cusps are separated a distance larger than
their screening lengths. Using the scattering matrix formalism, we obtain the
transmission and reflection amplitudes for the scattering processes of both
configurations. We show that, the presence of transmission resonances modifies
the Lorentizian shape of the energy resonances and induces the appearance of
additional maxima in the transmission coefficient in the range of energies
where transmission resonances occur. We calculate the Wigner time-delay and
show how their maxima depend on the position of the transmission resonance.Comment: To appear in Physica Script