815 research outputs found
Coulomb breakup effects on the elastic cross section of He+Bi scattering near Coulomb barrier energies
We accurately analyze the He+Bi scattering at 19 and 22.5 MeV
near the Coulomb barrier energy, using the continuum-discretized
coupled-channels method (CDCC) based on the ++He+Bi four-body
model.
The three-body breakup continuum of He is discretized by diagonalizing
the internal Hamiltonian of He in a space spanned by the Gaussian basis
functions.
The calculated elastic and total reaction cross sections are in good
agreement with the experimental data, while the CDCC calculation based on the
di-neutron model of He, i.e., the +He+Bi three-body
model, does not reproduce the data.Comment: 5 pages, 5 figures, uses REVTeX 4, submitted to Phys. Rev.
Strongly coupled phase transition in ferroelectric/correlated electron oxide heterostructures
We fabricated ultrathin ferroelectric/correlated electron oxide
heterostructures composed of the ferroelectric Pb(Zr0.2Ti0.8)O3 and the
correlated electron oxide (CEO) La0.8Sr0.2MnO3 on SrTiO3 substrates by pulsed
laser epitaxy. The hole accumulation in the ultrathin CEO layer was
substantially modified by heterostructuring with the ferroelectric layer,
resulting in an insulator-metal transition. In particular, our thickness
dependent study showed that drastic changes in transport and magnetic
properties were strongly coupled to the modulation of charge carriers by
ferroelectric field effect, which was confined to the vicinity of the
interface. Thus, our results provide crucial evidence that strong ferroelectric
field effect control can be achieved in ultrathin (10 nm) heterostructures,
yielding at least a 100,000-fold change in resistivity
Near-infrared Brightness of the Galilean Satellites Eclipsed in Jovian Shadow: A New Technique to Investigate Jovian Upper Atmosphere
We have discovered that Europa, Ganymede and Callisto are bright around 1.5
{\mu}m even when not directly lit by sunlight, based on observations from the
Hubble Space Telescope and the Subaru Telescope. The observations were
conducted with non-sidereal tracking on Jupiter outside of the field of view to
reduce the stray light subtraction uncertainty due to the close proximity of
Jupiter. Their eclipsed luminosity was - of their uneclipsed
brightness, which is low enough that this phenomenon has been undiscovered
until now. In addition, Europa in eclipse was <1/10 of the others at 1.5
{\mu}m, a potential clue to the origin of the source of luminosity. Likewise,
Ganymede observations were attempted at 3.6 {\mu}m by the Spitzer Space
Telescope but it was not detected, suggesting a significant wavelength
dependence. The reason why they are luminous even when in the Jovian shadow is
still unknown, but forward-scattered sunlight by haze in the Jovian upper
atmosphere is proposed as the most plausible candidate. If this is the case,
observations of these Galilean satellites while eclipsed by the Jovian shadow
provide us a new technique to investigate Jovian atmospheric composition, and
investigating the transmission spectrum of Jupiter by this method is important
for investigating the atmosphere of extrasolar giant planets by transit
spectroscopy.Comment: 7 pages, 3 figures, accepted to Ap
First-Principles Study on Electron Conduction in Sodium Nanowire
We present detailed first-principles calculations of the electron-conduction
properties of a three-sodium-atom nanowire suspended between semi-infinite
crystalline Na(001) electrodes during its elongation. Our investigations reveal
that the conductance is ~1 G0 before the nanowire breaks and only one channel
with the characteristic of the orbital of the center atom in the nanowire
contributes to the electron conduction. Moreover, the channel fully opens
around the Fermi level, and the behavior of the channel-current density is
insensitive to the structural deformation of the nanowire. These results verify
that the conductance trace as a function of the electrode spacing exhibits a
flat plateau at ~1 G0 during elongation.Comment: 8 pages, 5 figure
Evidence for a universal length scale of dynamic charge inhomogeneity in cuprate superconductors
Time-resolved optical experiments can give unique information on the
characteristic length scales of dynamic charge inhomogeneity on femtosecond
timescales. From data on the effective quasiparticle relaxation time r
in La2-xSrxCuO4 and Nd2-xCexCuO4 we derive the temperature- and doping-
dependence of the intrinsic phonon escape length le, which, under certain
circumstances, can be shown to be a direct measure of charge inhomogeneity.
Remarkably, a common feature of both p and n-type cuprates - which has
important consequences for superconductivity - is that as T  Tc from
above, the escape length approaches the zero-temperature superconducting
coherence length, le  s(0). In close vicinity of Tc, le appears
to follow the critical behaviour of the Ginsburg-Landau coherence length,
GL(T). In the normal state le is found to be in excellent agreement
with the mean free path lm obtained from the resistivity data. The data on le
also agree well with the data on structural coherence lengths ls obtained from
neutron scattering experiments, implying the existence of complex intrinsic
textures on different length scales which may have a profound effect on the
functional properties of these materials.Comment: To appear in Physical Review Letter
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