Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Thick films (10–12 μm) of NiZn–ferrite (Ni0.6Zn0.4Fe2O4) were grown on single-crystal (100) magnesium oxide substrates using pulsed laser deposition (PLD). The morphology, phase, orientation, strain, and magnetic properties of the as-deposited films were investigated as a function of substrate temperature (400–700 °C)…
The fcc to bcc structural change in the growth of ultrathin iron films is studied for films grown on a (111) fcc surface, in an attempt to mimic the geometry of the martensitic transition in bulk iron, where the interface is formed from the close-packed planes of the two structures. The use of a 2-ML Ni/W(110) substra…
A previously proposed approach for the ab initio evaluation of Hubbard parameters is applied to BEDT-TTF dimers. The dimers are positioned according to four geometries taken as the first neighbors from the experimental data on the κ-(BEDT-TTF)2Cu[N(CN)2]Br crystal. RHF-SCF, CAS-SCF and frozen-orbital calculations usin…
We present a mathematical model to describe the optical phase shift induced by polymer dispersed liquid crystals (PDLCs) on light impinging transversely on the sample. PDLCs are dispersions of liquid crystal microdroplets in a polymeric binder. Droplets appear as optically uniaxial spheres randomly oriented so that th…
The effect of laser intensity on the deposition of diamondlike carbon (DLC) films has been studied using an ArF (193 nm) pulsed excimer laser. Our results are found to be distinct from other studies using Nd-YAG infrared or excimer 248-nm lasers. Two issues concerning the growth mechanism of the films are discussed: (…
Electronic and structural properties of transition-metal/${\mathrm{BaTiO}}_{3}$(001) interfaces are studied by first-principles local-density full-potential linearized augmented plane-wave calculations with slab models. Equilibrium interlayer separations between metal overlayers (for the 5d metals Ta, W, Ir, and Pt) a…
The diffusion of doubly charged nickel vacancies in a \ensuremath{\Sigma}5(310)[001] tilt grain boundary (GB) of NiO has been studied by molecular dynamics. The simulations are carried out in the NVT ensemble (constant number of particles, volume, and temperature) and the interatomic interactions are described by a ri…
The technical relevance of Rh, Pd, and Pt as catalysts used to reduce ${\mathrm{NO}}_{\mathrm{x}}$ pollutants has stimulated great interest in a detailed understanding of the chemisorption process of these systems. While experiment indicates Rh to be a better catalyst than the other transition metals, theory still doe…
A chair-within-a-chair arrangement of the twelve copper atoms (bottom left) is characteristic of one of the complexes reported here; the other complex features two Cu tetrahedra sharing a common vertex (bottom right). Both were isolated from the reaction mixture [Cu2(O2CMe)4(H2O)2]/(py)2CO in MeCN. Magnetic susceptibi…
Polarized fluorescence spectra produced by site-selective excitation, and conventional polarized absorption spectra were obtained for Tm3+ and Er3+ ions individually incorporated into single crystals of strontium fluorapatite, Sr5(PO4)3F, also known as SFAP. Substitution of the trivalent rare earth ion for divalent st…
A simple effective Hamiltonian for the electron-phonon coupling in the conjugated polymers is derived from the Su-Schrieffer-Heeger model with quantized lattice motions. Phonons correspond to lattice quantum fluctuations around the dimerized positions. Both acoustic and optical modes are considered. The energy-momentu…
The optical transitions of vanadium ${\mathrm{V}}^{4+}$(${3\mathrm{d}}^{1}$) on the hexagonal lattice site (h) of 6H-silicon carbide are studied by Fourier-Zeeman spectroscopy. The Zeeman splitting of the four zero-phonon lines is completely resolved. We first obtain the effective g factors from the Zeeman splitting.…
The natural mineral cetineite was prototype for the synthesis of the compound 1. Its nanoporous, template-free host structure is an idela object for numerous investigations. Electronic excitation and transport processes, for example, can be studied on this nanostructured semiconducting material. A part of the crystal…
The photoelectrochemical properties of a p-type silicon (100) electrode coated with tungsten oxide thin film were investigated as a function of annealing temperature. The variation in the annealing temperature affected the photocurrent of a WO3/p-Si electrode. A maximum photocurrent was obtained when the 500 Å WO3 thi…
Infrared transmission spectra were measured systematically in polycrystalline La1−xCaxMnO3−δ and several systems substituted by other rare earth (RE) ions such as Sm3+, Gd3+, Dy3+, etc., at La3+ sites or Fe ions at Mn sites but keeping the nominal Mn4+/Mn3+≈3/7. Two strong absorption peaks located around 600 and 350 c…
The \ensuremath{\pi}-electronic excitations of graphite layers are studied within the random-phase approximation. They principally reflect the \ensuremath{\pi}-band characteristics, the strong wave-vector dependence, the anisotropic behavior, and the special symmetry. The \ensuremath{\pi} plasmons in graphite have str…
We have used infrared (IR) absorption spectra to characterize a-C:H and its alloys (a-C:H,N,F). The samples were deposited in an rf plasma-enhanced chemical-vapor deposition system with various mixtures of ${\mathrm{CH}}_{4}$, ${\mathrm{N}}_{2}$, and ${\mathrm{NF}}_{3}$ gases. IR spectra are analyzed in detail and the…
In real metals with interacting conduction electrons a Fermi surface (FS) can no longer be defined as separating occupied from unoccupied one-electron states in k space, but is rather given by the location of discontinuities in the momentum distribution function n(k). Here we show that this many-body theoretical defin…
A comparative study of photoluminescence (PL) and photoluminescence excitation (PLE) spectra of porous silicon (PS) and Si oxide, both emitting blue light, is reported. The PLE spectrum of Si oxide monitored at 460 nm displays a three-peak structure with peak wavelengths around 265, 300, and 360 nm. The PLE intensity…
Extended x-ray-absorption fine structure (EXAFS), Fourier-transform infrared absorption (FTIR), and elemental analysis were used on a variety of CdSe nanocrystallites (NC's) to study surface structure. All CdSe NC's were grown by standard inverse micelle techniques. Two sets of NC's samples were made. One set was made…