We study the transfer of spectral weight in the optical spectra of a strongly correlated electron system as a function of temperature and interaction strength. Within a dynamical mean field theory of the Hubbard model that becomes exact in the limit of large lattice coordination, we predict an anomalous enhancement of spectral weight as a function of temperature in the correlated metallic state...

The new family of unconventional iron-based superconductors discovered in 2006 immediately relieved their copper-based high-temperature predecessors as the most actively studied superconducting compounds in the world. The experimental and theoretical effort made in order to unravel the mechanism of superconductivity in these materials has been overwhelming. Although our understanding of their m...

The optical conductivity of high quality decagonal quasicrystals of Ales Co&qCu&s and A162Co~5CupoSi3 shows a strong anisotropy between the periodic and the quasiperiodic directions. We suggest that this is due to the dramatic enhancement of scattering in the quasiperiodic planes. The analysis of the conductivity reveals a drastic difFerence between the electronic structure of the decagonal qua...

In order to facilitate the development of next-generation display devices or modern solar cells, material performance is critically important. A combination of high transparency in the optical spectral range and high electrical conductivity under ambient conditions is attractive, if not crucial, for many applications. While the doping-induced presence of free electrons in the conduction bands o...

We show that the origin of the universal optical conductivity in a normal N-layer graphene multilayer is an emergent chiral symmetry which guarantees that sigma(omega) = Nsigma_{uni} in both low and high-frequency limits. [sigma_{uni} = (pi/2)e;{2}/h]. We use this physics to relate intermediate frequency conductivity trends to qualitative characteristics of the multilayer stacking sequence.

The optical reflectivity of a vacancy doped colossal magnetoresistance material La0.936Mn0.982O3 has been investigated on single-crystal samples as a function of temperature and at zero and 0.5 T magnetic fields. The conductivity has been evaluated by Kramers-Kronig analysis in the frequency range of 100–20 000 cm. The broad peak in the optical conductivity, observed at room temperature around ...

CdxZn8-xTe92chalcogenideglass is prepared by melt quenching technique. The thin films of as-prepared glass are deposited by thermal evaporation technique under the vacuum better than 10torr. The optical parameters such as refractive index (n), extinction coefficient (k), the absorption coefficient (α), and optical band gap (Eg) are calculated from transmittance spectra in the 200-1800nm region....

in this study we investigate the effect of atoms such as b, n, ge and sn on the optical and the electrical properties of capped (5, 0) zigzag carbon nanotube, using dft calculation method. these elements were attached to the one end of the carbon nanotube. we considered four different structure designs as possible candidates for a p-n junction device. the electrical properties of these structur...

The aim of the present study was to evaluate the properties of linear andnonlinear optics of the Schiff base Salen. Crystal structure of nanoparticles wasdetermined by a Bruker make diffractometer, Cu-K X-rays of wavelength (=1.5406Å). The XRD patterns were recorded in the 2 range of 10–90o with a step width of 0.02s-1. The UV-Vis Spectra recorded on a computerized double - beam Shimadzu 255...

We studied the changes in the dc resistivity, Raman scattering, and IR conductivity of single crystals of YBa2Cu306.95 induced by damage from low-energy He + ion bombardment. It appears that T~., transport properties, and optical conductivity are strongly affected by modest irradiation doses whereas the chemical composition of the sample is not modified. Carrier localization is evidenced by the...