1,768 research outputs found
Experimentally observed evolution between dynamic patterns and intrinsic localized modes in a driven nonlinear electrical cyclic lattice
Locked intrinsic localized modes (ILMs) and large amplitude lattice spatial
modes (LSMs) have been experimentally measured for a driven 1-D nonlinear
cyclic electric transmission line, where the nonlinear element is a saturable
capacitor. Depending on the number of cells and electrical lattice damping a
LSM of fixed shape can be tuned across the modal spectrum. Interestingly, by
tuning the driver frequency away from this spectrum an LSM can be continuously
converted into ILMs and visa versa. The differences in pattern formation
between simulations and experimental findings are due to a low concentration of
impurities. Through this novel nonlinear excitation and switching channel in
cyclic lattices either energy balanced or unbalanced LSMs and ILMs may occur.
Because of the general nature of these dynamical results for nonintegrable
lattices applications are to be expected. The ultimate stability of driven aero
machinery containing nonlinear periodic structures may be one example.Comment: 7 pages 7 figure
Effect of cation size variance on spin and orbital order in Eu(LaY)VO
We have investigated the -ion ( = rare earth or Y) size variance effect
on spin/orbital order in Eu(LaY)VO. The
size variance disturbs one-dimensional orbital correlation in -type
spin/-type orbital ordered states and suppresses this spin/orbital order. In
contrast, it stabilizes the other spin/orbital order. The results of neutron
and resonant X-ray scattering denote that in the other ordered phase, the
spin/orbital patterns are -type/-type, respectively.Comment: 4 pages, 4 figures, accepted to Rapid Communication in Physical
Review
Anisotropic Optic Conductivities due to Spin and Orbital Orderings in LaVO3 and YVO3: First-Principles Studies
The anisotropy of low energy (05eV) optical excitations in strongly
correlated transition-metal oxides is closely related to the spin and orbital
orderings. The recent successes of LDA+ method in describing the magnetic
and electronic structures enable us to calculate the optical conductivity from
first-principles. The LaVO and YVO, both of which have
configuration and have various spin and orbital ordered phases at low
temperature, show distinct anisotropy in the optical spectra. The effects of
spin and orbital ordering on the anisotropy are studied in detail based on our
first-principles calculations. The experimental spectra of both compounds at
low temperature phases can be qualitatively explained with our calculations,
while the studies for the intermediate temperature phase of YVO suggest the
substantial persistence of the low temperature phase at elevated temperature.Comment: 6 pages, 3 figures, accepted by PR
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