29,721 research outputs found
Impurity scattering and Friedel oscillations in mono-layer black phosphorus
We study the effect of impurity scattering effect in black phosphorurene (BP)
in this work. For single impurity, we calculate impurity induced local density
of states (LDOS) in momentum space numerically based on tight-binding
Hamiltonian. In real space, we calculate LDOS and Friedel oscillation
analytically. LDOS shows strong anisotropy in BP. Many impurities in BP are
investigated using -matrix approximation when the density is low. Midgap
states appear in band gap with peaks in DOS. The peaks of midgap states are
dependent on impurity potential. For finite positive potential, the impurity
tends to bind negative charge carriers and vise versa. The infinite impurity
potential problem is related to chiral symmetry in BP
Rans-Based Numerical Simulation of Captive Model Tests in Shallow Water for the DCT Container Carrier
Vector magnetic field sensing by single nitrogen vacancy center in diamond
In this Letter, we proposed and experimentally demonstrated a method to
detect vector magnetic field with a single nitrogen vacancy (NV) center in
diamond. The magnetic field in parallel with the axis of the NV center can be
obtained by detecting the electron Zeeman shift, while the Larmor precession of
an ancillary nuclear spin close to the NV center can be used to measure the
field perpendicular to the axis. Experimentally, both the Zeeman shift and
Larmor precession can be measured through the fluorescence from the NV center.
By applying additional calibrated magnetic fields, complete information of the
vector magnetic field can be achieved with such a method. This vector magnetic
field detection method is insensitive to temperature fluctuation and it can be
applied to nanoscale magnetic measurement.Comment: 5 pages, 5 figure
Role of the (1535) in the and reactions
We study the and
reactions with a unitary chiral approach. We find that the unitary chiral
approach, which generates the dynamically, can describe the data
reasonably well, particularly the ratio of the integrated cross sections. This
study provides further support for the unitary chiral description of the
. We also discuss some subtle differences between the coupling
constants determined from the unitary chiral approach and those determined from
phenomenological studies.Comment: version to appear in PRC; certain features of the approach clarifie
Rotational Doppler effect in left-handed materials
We explain the rotational Doppler effect associated with light beams carrying
with orbital angular momentum in left-handed materials (LHMs). We demonstrate
that the rotational Doppler effect in LHMs is unreversed, which is
significantly different from the linear Doppler effect. The physics underlying
this intriguing effect is the combined contributions of negative phase velocity
and inverse screw of wave-front. In the normal dispersion region, the
rotational Doppler effect induces a upstream energy flow but a downstream
momentum flow. In the anomalous dispersion region, however, the rotational
Doppler effect produces a downstream energy flow but a upstream momentum flow.
We theoretically predict that the rotational Doppler effect can induce a
transfer of angular momentum of the LHM to orbital angular momentum of the
beam.Comment: 6 pages, 3 figure
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