Materials Literature
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A systematic study of porous silicon anodic oxidation is reported. We have studied the evolution of the lattice parameter versus oxidation levels for p- and p+-type materials by using high-resolution x-ray diffraction, which gives a determination of the strains of the porous layer. The analysis of an asymmetric reflec…
Laser deposition technique has been applied to synthesize (Sr0.2Ba0.8)TiO3 thin films. The crystal structure of the films and the effect of deposition parameters on them have been systematically examined. Among the important deposition parameters, the substrate temperature and the chamber oxygen pressure affect the ch…
Small-angle x-ray scattering (SAXS) from single-phase melts and solutions of polystyrene-block-polyisoprene (SI) having various degrees of polymerization N and compositions f were analyzed on the basis of Landau-type mean-field theory developed by Leibler. The effective Flory interaction parameter χeff per segment in…
As an effective model to describe perovskite-type manganates (La,$A$)MnO$_3$, the double-exchange model on a cubic lattice is investigated. Spin excitation spectrum of the model in the ground state is studied using the spin wave approximation. Spin wave dispersion relation observed in the inelastic neutron scattering…
The reaction of excess trimethylgallium with acridine in diethyl ether gave the title layer inclusion compound, [Ga(CH 3 ) 3 (C 13 H 9 N)].0.5C 13 H 9 N. The Ga-N bond length is 2.203 (3) A.
Iron carbonitride (ICN) ultrafine particles (20–80 nm in size) have been synthesized by laser-induced pyrolysis of Fe(CO)5–NH3–C2H4 mixture. The surface morphology, structural characteristics, oxidation behavior, and the magnetic properties of the ICN particles were reported. The role the thin carbon layer formed on t…
The title compound, caesium lanthanum diniobium heptaoxide, belongs to the ARNb2O7 (A = K, Rb, Cs; R = La, Nd) family of compounds and crystallizes as a layered structure in which the Cs+ ions are located in the interlayer gap formed by double perovskite LaNb2O7 layers. The single-crystal X-ray refinement of the struc…
We present the results of a theoretical investigation of the electromigration wind force for adatom migration in a number of migrator-substrate systems. The theoretical background for our study follows from previous work done on bulk electromigration using the linear-response formalism of Kubo. We treat the electronic…
The origin of the cracking of highly porous silicon layers during drying is investigated. Optical and scanning electron microscopy observation allow us to observe the cracking occurrence. In situ x-ray diffraction experiments, under controlled vapor pressure of pentane, reveal that large capillary stresses occur at a…
The adsorption and temperature-dependent decomposition of ${\mathrm{SO}}_{2}$ on Cu(100) and Cu(111) have been studied by fast and high-resolution core-level photoemission. The analysis of the S 2p and O 1s data shows that molecular ${\mathrm{SO}}_{2}$ adsorption dominates at 170 K. On heating the ${\mathrm{SO}}_{2}$-…
We present converged first-principles calculations for the atomic and electronic structure of diamond (111) surfaces based on density-functional theory in the local-density approximation. Single- and triple-dangling- bond surfaces with 1\ifmmode\times\else\texttimes\fi{}1, 2\ifmmode\times\else\texttimes\fi{}1, and ($\…
Stable platinum oxide films have been prepared through magnetron sputtering and have been analyzed on the bases of energy-sensitive microanalyses, x-ray diffraction, resistivity, and optical reflectance measurements. The complex dielectric function has been determined for various oxygen contents in the film covering t…
Effect of curvature-induced strain on the covalent bonding in isolated and selected single-shell and multi- shell carbon nanotubes is explored, using electron energy-loss spectroscopy (EELS) on the core K level, which probes the distribution of available unoccupied states in the conduction band. Results show that the…
We have studied luminescence properties of nanometer-sized Si crystallites fabricated by laser breakdown of ${\mathrm{SiH}}_{4}$ gas. An exponential absorption tail is observed and red photoluminescence (PL) appears in the exponential tail. The PL decay behavior is characterized by a stretched exponential function. At…
Quantum-beat spectroscopy has been used to observe excited states of the N-V center in diamond. For the 1.945-eV optical transition, direct evidence is presented for the existence of GHz-scale fine structure, together with a much larger 46-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ level splitting in the E state. An i…
The orbital and spin orderings of ${\mathit{d}}^{2}$ Jahn-Teller systems are studied in the generalized gradient approximation (GGA) by using the full-potential linearized augmented-plane-wave method. For the low temperature distorted crystal structures in ${\mathrm{YVO}}_{3}$ and ${\mathrm{LaVO}}_{3}$ perovskites, we…
We introduce a novel polarizing beam splitter that uses the anisotropic spectral reflectivity (ASR) characteristic of a high-spatial-frequency multilayer binary grating. Such ASR effects allow us to design an optical element that is transparent for TM polarization and reflective for TE polarization. For normally incid…
Two-photon excitation spectra of highly monodisperse colloidal CdSe nanocrystals with sizes ranging from 22 to 43 \AA{} are compared to one-photon excitation data and to a spherically confined effective-mass model. The main experimental features are well described by this model. However, the first one-photon and two-p…
Melts of semiflexible AB diblock copolymers are studied using the wormlike chain model and self-consistent-field theory. The diblocks considered here are symmetric in composition and in A- and B-block flexibility. Under these conditions, the microstructure formed is lamellar. We find that an increase in molecular rigi…
In this work we present a theoretical justification, based on a two-state model, of the recently observed close resemblance between the molecular first-order hyperpolarizability (${\mathrm{\ensuremath{\beta}}}^{\mathit{e}}$) obtained with traditional experimental or theoretical methods and the vibrational (or relaxati…