6,201 research outputs found
Effect of disorder outside the CuO planes on of copper oxide superconductors
The effect of disorder on the superconducting transition temperature
of cuprate superconductors is examined. Disorder is introduced into the cation
sites in the plane adjacent to the CuO planes of two single-layer
systems, BiSrLnCuO and
LaNdSrCuO. Disorder is controlled by changing
rare earth (Ln) ions with different ionic radius in the former, and by varying
the Nd content in the latter with the doped carrier density kept constant. We
show that this type of disorder works as weak scatterers in contrast to the
in-plane disorder produced by Zn, but remarkably reduces suggesting
novel effects of disorder on high- superconductivity.Comment: 5 pages, 5 figures, to be published in Phys. Rev. Let
Compressional properties of nuclear matter in the relativistic mean field theory with the excluded volume effects
Compressional properties of nuclear matter are studied by using the mean
field theory with the excluded volume effects of the nucleons. It is found that
the excluded volume effects make it possible to fit the empirical data of the
Coulomb coefficient of nucleus incompressibility, even if the volume
coefficient is small(MeV). However, the symmetry properties favor
MeV as in the cases of the mean field theory of point-like
nucleons.Comment: PACS numbers, 21.65.+f, 21.30.+
Quantum-number projection in the path-integral renormalization group method
We present a quantum-number projection technique which enables us to exactly
treat spin, momentum and other symmetries embedded in the Hubbard model. By
combining this projection technique, we extend the path-integral
renormalization group method to improve the efficiency of numerical
computations. By taking numerical calculations for the standard Hubbard model
and the Hubbard model with next nearest neighbor transfer, we show that the
present extended method can extremely enhance numerical accuracy and that it
can handle excited states, in addition to the ground state.Comment: 11 pages, 7 figures, submitted to Phys. Rev.
Synchrotron X-ray diffraction study of a charge stripe order in 1/8-doped LaBaSrCuO
Lattice distortions associated with charge stripe order in 1/8 hole-doped
LaBaSrCuO are studied using synchrotron X-ray
diffraction for and . The propagation wave vector and charge
order correlation lengths are determined with a high accuracy, revealing that
the oblique charge stripes in orthorhombic crystal are more
disordered than the aligned stripes in tetragonal crystal. The twofold
periodicity of lattice modulations along the c-axis is explained by long-range
Coulomb interactions between holes on neighboring CuO planes.Comment: 4pages, 4figures, Submitted to PR
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