Materials Literature
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A combined study with use of time-domain pump-probe spectroscopy and time-domain terahertz transmission spectroscopy have been carried out on an underdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ thin film. It was observed that the low energy multi-excitation states were decomposed into superconducting gap and pseudogap. The ps…
We report a detailed study of the electronic structure of the MgB$_{2}$ with different lattice constants by using the full-potential linearized augmented plane wave(FPLAPW) method. It is found that the lattice parameters have great effect on the $σ$ band of Boron. Our results indicate that increasing lattice constant…
Ionic-pair equal-time displacement correlations in relaxor lead magnesium niobate, $\mathrm{Pb}({\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3}){\mathrm{O}}_{3},$ have been investigated at 300, 270, and 240 K in terms of an x-ray diffuse scattering technique. Functions of the distinct correlations have been determined quantita…
A beautiful and intriguing relationship has recently been proposed to express the critical screening lengths associated with the apparition of new bound states for the two-dimensional statically screened Coulomb potential. Semiclassical quantum theory show that this relationship is unfortunately not strictly exact. Th…
A modeling of the soil structure and surface roughness by means of the concepts of the fractal growth is presented. Two parameters are used to control the model: the fragmentation dimension, $D_f$, and the maximum mass of the deposited aggregates, $M_{max}$. The fragmentation dimension is related to the particle size…
We report valence and conduction band alignments and offsets for heterojunctions between CdCr2Se4, an n-type ferromagnetic semiconductor, and the non-magnetic materials Si and GaAs, evaluated using density functional theory. We explore numerically the impact of different interface features on the type of band alignmen…
Ab initio calculations are performed to elucidate the mechanism of the photoisomerization of azobenzene. We obtain the excitation energies of the S1(n→π*), S2(π→π*), and S3(n2→π*2) states by complete active space self-consistent field (CASSCF) and multireference single double configuration interaction (MRSDCI) calcula…
Thin films of CrSb grown by solid-source molecular-beam epitaxy on GaAs, (Al, Ga)Sb, and GaSb are found to exhibit ferromagnetism. Reflection high-energy electron diffraction and high-resolution cross sectional transmission electron microscopy both indicate that the structure is zincblende. Temperature dependence of r…
Thorough Raman and infrared (IR) reflectivity investigations of nominally pure ${\mathrm{SrTiO}}_{3}$ ceramics in the 10--300 K range have revealed a clear presence of the polar phase whose manifestation steeply increases on cooling. The Raman strengths of the Raman-forbidden IR modes are proportional to ${\ensuremath…
The crystal structure of 3-picoline (3-methylpyridine, C6H7N) has been determined at 120 (2) K following in situ crystal growth from the liquid. The molecules pack in a herring-bone-type arrangement in the non-centrosymmetric space group Pna21.
TEM analyses enable a priori investigation of smectic bilayer structures in an amorphous−liquid crystalline (LC) diblock copolymer. A newly synthesized copolymer with 85 wt % LC phase segregates into a layered morphology in both bulk and thin film studies. The microstructure has a periodicity of ∼70 Å and forms highly…
Computer simulations of systems of soft repulsive spherocylinders (SRS) of aspect ratio (L/D) equal to 4 have been carried out using the parallel molecular dynamics program GBMOLDD. At sufficiently high densities the system forms stable nematic and smectic-A liquid crystalline phases. Results are presented for a serie…
Silyl ether-coupled poly(epsilon-caprolactone)s (PCLs) with stepwise degradation profiles were synthesized via the cross-dehydrocoupling polymerizations between 1,4-bis(dimethylsilyl)benzene (BDSB) and telechelic, diol-terminated PCL macromonomers. With the presence of 10 wt % palladium on activated carbon as the cata…
Gold nanoclusters on MgO powder were prepared from adsorbed [Au(CH 3 ) 2 (C 5 H 7 O 2 )] and characterized by infrared and X-ray absorption spectroscopies. Treatment of the samples in He or H 2 at increasing temperatures removed CH 3 and C 5 H 7 O 2 ligands and caused the gold to aggregate into nanoclusters of increas…
The same intercalated structure, as determined by X-ray diffraction, is obtained whether EVA-based nanocomposites are prepared starting from an organo-modified montmorillonite (compound 1) or from a Na+ montmorillonite compatibilized by reactive processing using an alkylammonium bromide (compound 3) equivalent to the…
A new flexible approach is developed to fabricate uniform nanocrystals and nanowires of binary compound semiconductor PbS inside the channels of mesoporous silica SBA-15. The approach combines functionalization of the channel surface with thiol groups, absorption of Pb 2+, and heating in N 2 atmosphere at high tempera…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTEffect of Rehybridization on the Electronic Structure of Single-Walled Carbon NanotubesM. A. Hamon, M. E. Itkis, S. Niyogi, T. Alvaraez, C. Kuper, M. Menon, and R. C. HaddonView Author Information Departments of Chemistry and Chemical and Environmental Engineering Univ…
There is increasing interest in many-body perturbation theory as a practical tool for the calculation of ground-state properties. As a consequence, unambiguous sum rules such as the conservation of particle number under the influence of the Coulomb interaction have acquired an importance that did not exist for calcula…
We propose here a device for measuring the ellipticity of light. Its core element is a polarization diffraction grating. As far as we know, no other similar device has been developed so far. To record the grating holographically we used a Mordant Pure Yellow azodye in a matrix of gelatin. This media acquires relativel…
Abstract Poly(N‐substituted urethane)s with an alkyl or ligo(ethylene oxide) monomethyl ether side chain were synthesized by the reaction operating in the following two‐step process: first, by metalation of the starting polymer with potassium tertiary butoxide ( t ‐BuOK) and then by treatment of the obtained urethane…