167 research outputs found
MOLECULAR INSIGHTS INTO MIRNA PROCESSING BY ARABIDOPSIS THALIANA SERRATE AND DAWDLE
Ph.DDOCTOR OF PHILOSOPH
Dirac fermion reflector by ballistic graphene sawtooth-shaped npn junctions
We have realized a Dirac fermion reflector in graphene by controlling the
ballistic carrier trajectory in a sawtooth-shaped npn junction. When the
carrier density in the inner p-region is much larger than that in the outer
n-regions, the first straight np interface works as a collimator and the
collimated ballistic carriers can be totally reflected at the second zigzag pn
interface. We observed clear resistance enhancement around the np+n regime,
which is in good agreement with the numerical simulation. The tunable
reflectance of ballistic carriers could be an elementary and important step for
realizing ultrahigh-mobility graphene field effect transistors utilizing Dirac
fermion optics in the near future
Dynamic nuclear polarization and Knight shift measurements in a breakdown regime of integer quantum Hall effect
Nuclear spins are polarized electrically in a breakdown regime of an
odd-integer quantum Hall effect (QHE). Electron excitation to the upper Landau
subband with the opposite spin polarity flips nuclear spins through the
hyperfine interaction. The polarized nuclear spins reduce the spin-splitting
energy and accelerate the QHE breakdown. The Knight shift of the nuclear spins
is also measured by tuning electron density during the irradiation of
radio-frequency magnetic fields.Comment: 3 pages, 2 figures, EP2DS-1
- …