Neutron reflectivity studies of EuS/SrS, EuS/PbSe and EuS/PbTe all-semiconductor superlattices were carried out in a search for exchange interlayer coupling. A relatively weak antiferromagnetic coupling was found in EuS/SrS and EuS/PbSe systems but no interlayer coupling was detected in EuS/PbTe superlattices. In EuS/SrS, where the SrS spacer is an insulator (E(g)≈4 eV), a very weak and short r...

In order to confirm the picture of domain-wall excitations in the hidden antiferromagnetic order of the Haldane phase, the structure of the low-lying excitations in the S = 1 antiferromagnetic Heisenberg chain is studied by a quantum Monte Carlo method. It is confirmed that there exists a finite energy gap between the firstand the second-excited states at k = π as well as between the ground sta...

In order to reach the EU: s 20-20-20 primary energy savings target, energy efficiency needs to increase. Previous research on energy use and energy efficiency has focused mainly on the diffusion of energy efficient technologies. The discrepancy between optimal and actual implementation of energy efficient technologies has been illustrated in numerous articles and is often referred to as the ene...

The desired shifts of the boundaries of spectral allowed zones of periodical systems are demonstrated. In particular, the phenomenon of merging neighbor allowed zones is exhibited and its simple explanation is given. It is also shown how to change the additional fundamental spectral parameter, the degree of exponential solution growth, at arbitrary given energy points inside the forbidden zones...

the density of state and the natural bond orbital calculations were carried out to study theoxidation of co on au14 nano cluster through two different mechanisms and determining the bestmechanism for the reaction. chemisorption of o2 and co on the nano cluster led to change in energy,density of state and its thermodynamic properties. we calculated the energy band gap between thehighest occupied...

In this work facile sol-gel (pechni) method has been successfully established to synthesize Zn4B6O13 nanocrystals which have cubic crystals with lattice parameter: a =7.48 A. The structure and morphology of the obtained material were studied by X-ray diffraction (XRD), Infrared spectra (IR), scanning electron microscopy (SEM) and photoluminescence analysis. The experimental results show a band ...