Materials Literature
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A new theory is presented for describing band gaps and electronic structures of transition-metal compounds. A theoretical phase diagram is presented in which both the metallic sulfides and insulating oxides and halides occur in a quite natural manner.
For pt.I see ibid., vol.18, p.3943 (1985). The results in the preceding paper concerning the variation of the thermal conductivity, lambda , of six potassium and rubidium halides with temperature and pressure are analysed using a Leibfried-Schlomann formulation for the phonon-phonon scattering. The concept of a refere…
Abstract Bei dem Minimum der Liquidus‐Kurve bei 494 K und 50 Mol‐% KNO 3 handelt es sich um ein Pseudo‐Eutektikum, da die Subsolidusphase im gesamten Konzentrationsbereich aus Mischkristallen besteht.
Short-range order parameters for oxygen arrangement in a single crystal of ZrO 0.30 quenched from above the order-disorder transition temperature were determined by measurements of elastic neutron diffuse scattering. The preferential configurations of vacancy-oxygen atom pair are found at the first and second neighbor…
An unusual first-order Hall effect with the magnetic field parallel either to the current or to the Hall field is observed in monoclinic semimetallic ${\mathrm{SrAs}}_{3}$. Data are presented showing the dependence of this longitudinal Hall effect (LHE) on orientation, temperature, and magnetic field strength. Both sy…
Models for annealing processes in damaged, amorphous SiO2 are discussed. Using a series expansion approach, theories developed for diffusion-limited recombination are adapted to allow for a Gaussian distribution of activation energies. It is found that the effect of a distribution having deviation ΔE, and center EA ca…
We present an extensive study of Raman scattering by intervalley density fluctuations in n-type Si for a wide range of electron concentrations (8\ifmmode\times\else\texttimes\fi{}${10}^{18}$${\mathrm{eqN}}_{e}$${10}^{20}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$), temperatures (80--473 K), and laser frequencies (1.1…
We have studied the photophysics of a Zn(Cd)S:Ag phosphor, in powder form under ambient conditions, over a time domain extending from picoseconds to milliseconds. Pulsed laser luminescence techniques and time-resolved dielectric loss spectrometry have been employed. We propose mechanisms to interpret the results and c…
X-ray photoelectron (XPS) and electron-energy-loss spectroscopies have been employed to investigate the valence- and conduction-band densities of states of the sapphire (11\ifmmode\bar\else\textasciimacron\fi{}02) surface. The photoemission spectrum of the valence-band region has been adjusted to remove cross-section…
High-energy core-level Auger emission from adsorbed atoms on single-crystal surfaces is accompanied by diffraction and interference effects, similar to those observed in x-ray photoemission. We have used azimuthal anisotropies in the Cu(LMM) intensity at shallow polar angles and a kinematical scattering model to deter…
The optical transmittance of plasma-deposited composite gold--fluorocarbon-polymer thin films is analyzed in terms of effective-medium theories. The effect of increasing gold volume fraction is shown to be correctly described by the Sheng model, provided the gold-cluster and polymer-inclusion sizes and shapes analyzed…
X-ray photoelectron spectroscopy has been performed in order to investigate the effects of the chemical etching of GaAs {001} surfaces by the H2SO4/H2O2/H2O solution used following the procedure currently practiced in the molecular-beam-epitaxy technique. It is demonstrated that, in contrast to what is generally belie…
A Green's-function approach to nonlinear electronic transport in a static electric field is developed microscopically for the system composed of interacting electrons with impurities and phonons. The essential idea is to separate the center-of-mass motion from the relative motion of electrons. An electron temperature…
The results of an investigation of the transient mid-gap photoluminescence (PL) and photo-induced optical absorption in trigonal Se are presented. Direct evidence is found for a barrier of 35\ifmmode\pm\else\textpm\fi{}5 meV to trapping of free excitons at the PL center. All the features of the PL, including the high-…
The optical-absorption coefficient \ensuremath{\alpha}(\ensuremath{\omega}) in heavily doped n- and p-type GaAs is evaluated for comparison with the observed values of Casey et al. The purpose is to test the theory of electrons in heavily disordered systems derived by Sa-yakanit and the absorption matrix element (ME)…
The electronic structures of lithium metasilicate (${\mathrm{Li}}_{2}$${\mathrm{SiO}}_{3}$) and lithium disilicate (${\mathrm{Li}}_{2}$${\mathrm{Si}}_{2}$${\mathrm{O}}_{5}$) are calculated using a first-principles orthogonalized linear combination of atomic-orbitals method. Results are compared with experimental x-ray…
The 5D3–5D4 cross relaxation process of Tb3+ in CsCdBr3 has been evaluated by analysis of the decay curves of the 5D3 and 5D4 emission. The temperature dependence of the cross relaxation rate can be explained assuming phonon-assisted processes. The results show that the larger amount of Tb3+ ions is incorporated in pa…
In order to study the temperature and stress dependence of Young’s modulus in semiconducting barium titanate ceramics, the longitudinal sound velocity was measured at a frequency of 5 MHz in the temperature range of 20–180 °C. It is striking that at temperatures above the Curie point (Tc=120 °C) the sound velocity rea…
An exact solution of the random-phase-approximation equations is worked out for the density-density correlation function of a semi-infinite system of two-dimensional electron-gas layers, with different dielectrics outside and inside the layered system. From this solution, analytic formulas are derived for the dispersi…
Small multiprobe resistors have been fabricated from continuous metal films of Ag, Al, Au, Cr, Cu, Mo, Nb, Ni, Pt, and W deposited under various conditions. Each shows some reproducible level of flicker (1/f) noise. This study implicates carrier scattering by extrinsic defects or impurities as the source of the resist…