14,419 research outputs found
Focusing RKKY interaction by graphene P-N junction
The carrier-mediated RKKY interaction between local spins plays an important
role for the application of magnetically doped graphene in spintronics and
quantum computation. Previous studies largely concentrate on the influence of
electronic states of uniform systems on the RKKY interaction. Here we reveal a
very different way to manipulate the RKKY interaction by showing that the
anomalous focusing - a well-known electron optics phenomenon in graphene P-N
junctions - can be utilized to refocus the massless Dirac electrons emanating
from one local spin to the other local spin. This gives rise to rich spatial
interference patterns and symmetry-protected non-oscillatory RKKY interaction
with a strongly enhanced magnitude. It may provide a new way to engineer the
long-range spin-spin interaction in graphene.Comment: 9 pages, 4 figure
Effects of long-range Coulomb interaction on the quantum transport in fractional quantum Hall edges
We study the effects of long-range Coulomb interaction (LRCI) on the quantum
transport in FQH edges with . We consider two models, i.e., the
quasi-particle tunneling (QPT) model and the electron tunneling (ET) model at
the point contact. The tunneling conductance is obtained using the
renormalization group treatment. In QPT model, it is found that LRCI further
reduces below a crossover temperature . In ET model, on the
other hand, there is a temeperature region where LRCI enhances , and
nonmonotonic temperature dependence is possible.Comment: 4 pages, latex file. Published in Solid State Commun.103, 663 (1997).
There is a typo in the effective action for the ET model in the earlier
version. should be replaced by $1/\nu
Study of the hidden-heavy pentaquarks and states
In light of the recently observed resonance states and by LHCb Collaboration in
decay channel, we perform a systematical study of all possible
hidden-heavy pentaquarks with strangeness , in unified framework
of MIT bag model. The color-spin wavefunctions presented in terms of
Young-Yamanouchi bases and transformed into baryon-meson couplings, are
utilized to calculate masses, magnetic moments and ratios of partial widths.
With numerical analysis, the observed is likely
to be a compact pentaquark, and favors
two-peak structure of and states. Further predictions
on hadron properties and decay channels are given to compact ,
states and bottom sectors.Comment: 14 pages, 11 tables, 1 figure and two appendices, created by RevTex
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