Materials Literature
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By analyzing interference structures in low-energy electron-transmission spectra, we made a direct experimental determination of the electronic band structure in the (111) direction of argon films and possibly in the same direction for methane films in the energy range 0--10 eV relative to vacuum.
A new ordered state characterized by sharp electron diffraction spots showing an arrangement with a twelvefold symmetry axis inconsistent with the existence of a Bravais lattice has been found in small particles of Ni-Cr. Electron microscopic high-resolution structure images of these particles reveal that this orderin…
The nature of chain folding in polymers and the determination of the chain length at which folding occurs have been central questions in polymer science. The study of the formation of lamellar polymer crystals through chain folding has received a new impetus as a result of the recent synthesis of normal alkanes of str…
Abstract Detrital clay minerals alter systematically during burial diagenesis. Smectites evolve via intermediate ‘illite-smectites’ to illite. Trioctahedral ‘smectite-chlorites’ or ‘vermiculite-chlorites’ evolve towards true (polytype Ib) chlorites. In other reactions, authigenic clays (kaolinite, illite, chlorite) pr…
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…