in order to study some theories about nonsuperconductivity of prba2cu3o7, based on the density functional theory and with apw+lo/lapw method some calculations for prba2cu3o7 (pr123) and yba2cu3o7 (y123) were performed. the lsda+u approximation was used for pr(4f) orbitals and the effect of changing upr on the band structure, pr(4f)-dos, distribution of electrons on the planes and chains, and pr...

We study the electronic excitations near the charge-transfer gap in insulating CuO 2 planes, starting from a six-band model which includes p π and d xy orbitals and Cu-O nearest-neighbor repulsion U pd. While the low lying electronic excitations in the doped system are well described by a modified t−J model, the excitonic states of the insulator include hybrid d xy − p π states of A 2g symmetry...

We use the Gutzwiller variational theory to calculate the ground-state phase diagram and quasiparticle bands of LaOFeAs. The Fe3d-As4p Wannier-orbital basis obtained from density-functional theory defines the band part of our eight-band Hubbard model. The full atomic interaction between the electrons in the iron orbitals is parametrized by the Hubbard interaction U and an average Hund's-rule in...

Quantum corrections to the transverse spin-fluctuation propagator are obtained by including self-energy and vertex corrections to first order within a spin-rotationallysymmetric inverse-degeneracy (1/N ) expansion scheme which preserves the Goldstone mode order by order. A correlation-induced exchange-energy correction is shown to yield the dominant quantum reduction in the spin stiffness, prov...

We present results of the observations of the star 15 Mon, obtained with the aim of checking the impact of red leaks in the UV (and U-band) and two narrow-band filters on ACS CCDs. The red leak in the F220W, F250W and F330W filters appears to be smaller than measured in pre-flight tests. We derive updated passbands for the three filters and we present the updated correction table for different ...

this paper presents an e-ring shaped printed monopole antenna for uwb applications with dual notched bands performance. in order to generate single frequency band notch function, we applied a u-ring shaped monopole antenna, and by inserting a rectangular ring in the centre of it an e-ring shaped radiating patch created and a dual band-notch function can be achieved. the measured bandwidth of th...

Many-body perturbation theory in the GW approach is applied to lanthanide oxides, using the local-density approximation plus a Hubbard U correction (LDA+U) as the starting point. Good agreement between the G0W0 density of states and experimental spectra is observed for CeO2 and Ce2O3. Unlike the LDA+U method G0W0 exhibits only a weak dependence on U in a physically meaningful range of U values....