8,005 research outputs found
Metallic proximity effect in ballistic graphene with resonant scatterers
We study the effect of resonant scatterers on the local density of states in
a rectangular graphene setup with metallic leads. We find that the density of
states in a vicinity of the Dirac point acquires a strong position dependence
due to both metallic proximity effect and impurity scattering. This effect may
prevent uniform gating of weakly-doped samples. We also demonstrate that even a
single-atom impurity may essentially alter electronic states at low-doping on
distances of the order of the sample size from the impurity.Comment: 9 pages, 2 figure
Ballistic charge transport in chiral-symmetric few-layer graphene
A transfer matrix approach to study ballistic charge transport in few-layer
graphene with chiral-symmetric stacking configurations is developed. We
demonstrate that the chiral symmetry justifies a non-Abelian gauge
transformation at the spectral degeneracy point (zero energy). This
transformation proves the equivalence of zero-energy transport properties of
the multilayer to those of the system of uncoupled monolayers. Similar
transformation can be applied in order to gauge away an arbitrary magnetic
field, weak strain, and hopping disorder in the bulk of the sample. Finally, we
calculate the full-counting statistics at arbitrary energy for different
stacking configurations. The predicted gate-voltage dependence of conductance
and noise can be measured in clean multilayer samples with generic metallic
leads.Comment: 6 pages, 5 figures; EPL published versio
The influence of Galactic aberration on precession parameters determined from VLBI observations
The influence of proper motions of sources due to Galactic aberration on
precession models based on VLBI data is determined. Comparisons of the linear
trends in the coordinates of the celestial pole obtained with and without
taking into account Galactic aberration indicate that this effect can reach 20
as per century, which is important for modern precession models. It is
also shown that correcting for Galactic aberration influences the derived
parameters of low-frequency nutation terms. It is therefore necessary to
correct for Galactic aberration in the reduction of modern astrometric
observations
Dirac-Kronig-Penney model for strain-engineered graphene
Motivated by recent proposals on strain-engineering of graphene electronic
circuits we calculate conductivity, shot-noise and the density of states in
periodically deformed graphene. We provide the solution to the
Dirac-Kronig-Penney model, which describes the phase-coherent transport in
clean monolayer samples with an one-dimensional modulation of the strain and
the electrostatic potentials. We compare the exact results to a qualitative
band-structure analysis. We find that periodic strains induce large pseudo-gaps
and suppress charge transport in the direction of strain modulation. The
strain-induced minima in the gate-voltage dependence of the conductivity
characterize the quality of graphene superstructures. The effect is especially
strong if the variation of inter-atomic distance exceeds the value a^2/l, where
a is the lattice spacing of free graphene and l is the period of the
superlattice. A similar effect induced by a periodic electrostatic potential is
weakened due to Klein tunnelling.Comment: 11 pages, 8 figure
Plasmonic shock waves and solitons in a nanoring
We apply the hydrodynamic theory of electron liquid to demonstrate that a
circularly polarized radiation induces the diamagnetic, helicity-sensitive dc
current in a ballistic nanoring. This current is dramatically enhanced in the
vicinity of plasmonic resonances. The resulting magnetic moment of the nanoring
represents a giant increase of the inverse Faraday effect. With increasing
radiation intensity, linear plasmonic excitations evolve into the strongly
non-linear plasma shock waves. These excitations produce a series of the well
resolved peaks at the THz frequencies. We demonstrate that the plasmonic wave
dispersion transforms the shock waves into solitons. The predicted effects
should enable multiple applications in a wide frequency range (from the
microwave to terahertz band) using optically controlled ultra low loss
electric, photonic and magnetic devices.Comment: 13 pages, 12 figure
Electric dipole moment of the electron in YbF molecule
Ab initio calculation of the hyperfine, P-odd, and P,T-odd constants for the
YbF molecule was performed with the help of the recently developed technique,
which allows to take into account correlations and polarization in the
outercore region. The ground state electronic wave function of the YbF molecule
is found with the help of the Relativistic Effective Core Potential method
followed by the restoration of molecular four-component spinors in the core
region of ytterbium in the framework of a non-variational procedure. Core
polarization effects are included with the help of the atomic Many Body
Perturbation Theory for Yb atom. For the isotropic hyperfine constant A,
accuracy of our calculation is about 3% as compared to the experimental datum.
The dipole constant Ad (which is much smaller in magnitude), though better than
in all previous calculations, is still underestimated by almost 23%. Being
corrected within a semiempirical approach for a perturbation of 4f-shell in the
core of Yb due to the bond making, this error is reduced to 8%. Our value for
the effective electric field on the unpaired electron is 4.9 a.u.=2.5E+10 V/cm.Comment: 7 pages, REVTE
Conductance through the disclination dipole defect in metallic carbon nanotubes
The electronic transport properties of a metallic carbon nanotube with the
five-seven disclination pair characterized by a lattice distortion vector are
investigated. The influence of the disclination dipole includes induced
curvature and mixing of two sublattices. Both these factors are taken into
account via a self-consistent perturbation approach. The conductance and the
Fano factor are calculated within the transfer-matrix technique. PACS:
73.63.Fg, 72.80.Rj, 72.10.F
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