Materials Literature
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Dielectric constants and D - E hysteresis loops have been measured on trichloroacetamide (TCAA) single crystals. Only along the crystallographic b -axis are remarkable dielectric anomalies found at T C =354.6 K and T I =356.9 K upon heating. The Curie-Weiss relation holds in the high-temperature phase with a very smal…
An anomalous behavior was found in the temperature dependence of the ESR spectrum and the electric resistance of (BEDT-TTF) 2 RbHg(SCN) 4 below 20 K. The anomaly was compared with that of the isostructural salt [(BEDT-TTF) 2 KHg(SCN) 4 ] and based on the similarity of the anomaly between the Rb and the K salts, the po…
The high-pressure behavior of the direct and indirect band gaps in zinc-blende-structure SiC is examined with use of self-consistent ab initio pseudopotential calculations. The fundamental band gap from ${\mathrm{\ensuremath{\Gamma}}}_{15}^{\mathit{v}}$ to ${\mathit{X}}_{1}^{\mathit{c}}$ is found to decrease linearly…
The deposition of low-energy carbon atoms onto a low-temperature diamond (111) surface is studied by molecular-dynamics computer simulations. A Stillinger–Weber potential [F. H. Stillinger and T. A. Weber, Phys. Rev. B 31, 5262 (1985)], with a reparametrization derived from quantum-mechanical energy calculations for s…
We show that Brillouin scattering can be used to measure the elastic and optical properties of materials to very high temperatures. We have measured the elastic constants C11, C33, and C44 of single-crystal sapphire in the temperature range 300–2100 K extending by 300 K the highest temperature previously attained with…
The results of numerical simulations of two high-rate diamond growth environments (oxygen-acetylene torch and dc arcjet) are reported. The calculations account in detail for boundary-layer transport, gas-phase chemistry, and gas-surface chemistry. Diamond growth rates are calculated self-consistently with the gas-phas…
The electrical resistivity and thermopower have been measured on semiconducting mono- and polycrystalline FeWO 4 between approximately=100 K and approximately=1000 K. The DC resistivity rho , with activation energies E A approximately=0.15-0.32 eV and rho (294 K) approximately=5*10 2 -10 5 Omega cm, is probably govern…
The energy dispersion relation of the local interface plasmon modes of two coupled semi-infinite periodic arrays of quantum wells separated by a distance d has been calculated. An exact solution is obtained when the two semi-infinite superlattices have equivalent periodicities and dielectric constants, but different d…
Raman spectra were measured on bulk Na2O⋅(2−x)SiO2⋅xGeO2 glasses, where x varied from 0 to 2, and on Na2O⋅SiO2⋅xGeO2 glasses, where x varied from 0 to 1. Raman spectra were measured also on Na2O⋅(1−x)SiO2⋅xGeO2 glasses crystallized at 650 °C, mostly a solid solution with the β-Na2Si2O5 structure at x between 0 and 1.5…
A previously published analysis of the energy levels of Sm3+ in Y3Al5O12 (YAG) has been extended to include the 4G5/2 multiplet. New absorption and emission data are reported, and some previously reported levels have been reassigned. A theoretical calculation of intensities of emitted radiation originating at the 4G5/…
Hydrogen, deuterium, and helium were implanted at 5 K with energies from 0.25 to 3 keV into thin films of 80–320 nm of gold and tungsten. The annealing of the implantation-induced resistivity was measured during isochronally heating of the specimens up to 400 K. The onset of resistivity annealing after implantation to…
Viewing the brittle-to-ductile transition of fracture in intrinsically brittle solids as a crack tip initiated critical event of either nucleation of dislocation loops from the crack tip or the motion away of such dislocations from the crack tip, experiments have been devised to measure the critical activation energy…
The potassium ions of potassium titanyl phosphate (KTiOPO4, or KTP) are relatively mobile and may be exchanged with other ions from molten salts. Distribution coefficients for potassium, rubidium, barium, and strontium between nitrate melts and titanyl phosphate were measured between 350 and 425 °C. At 425 °C, using m…
The current-voltage (I-V) characteristics of silicon-incorporated polyethylene films fabricated by plasma polymerization have been measured at very high electric fields. The experimental results show that the electric conduction at high fields is due mainly to Fowler–Nordheim type tunneling injection of holes from the…
The adsorption, thermal reactions, and photoreactions of NO on Ag(111) and Cu(111) at 80–85 K have been studied by thermal-desorption spectroscopy (TDS), high-resolution electron-energy-loss spectroscopy (HREELS), and photon-induced desorption. Adsorption of NO on both surfaces is quite complicated. At saturation cove…
The concentration pair correlation function and the order–disorder transition in a diblock copolymer melt are studied in the framework of a self-consistent one-loop approximation. In contrast with earlier work, no simplifying assumption on the wave vector dependence of the correlation functions is made. This allows us…
Resonant tunneling involving discrete quantum states in microcrystalline-Si (\ensuremath{\mu}c-Si) with a-${\mathrm{SiO}}_{2}$ barriers is observed experimentally. The low interface trap densities, and the high barrier height between Si and a-${\mathrm{SiO}}_{2}$, allow the observation of several aspects in the physic…
The vibrational energies of the alkali-metal atoms in graphite intercalation compounds have been analyzed to yield effective temperatures ${\mathrm{T}}_{\mathrm{\ensuremath{\parallel}}}$ and ${\mathrm{T}}_{\mathrm{\ensuremath{\perp}}}$ and the corresponding Debye temperatures ${\mathrm{\ensuremath{\Theta}}}_{\mathrm{\…
We have studied reactive ion etching of Si1−xGex alloys with x≤0.15 and Ge in HBr plasmas. The etch rate of SiGe increases monotonically with the Ge content of the alloy and for a Si85Ge15 alloy was ≂50% greater than for Si. Etch profiles are identical to those formed in singe-crystal Si. X-ray photoelectron spectrosc…
We report measurements of the thermoelectric power and conductivity of ‘‘new’’ polyacetylene doped with iodine. In highly doped samples in which the conductivity extrapolates to finite values at zero temperature, we observe a nonlinearity in the thermopower very similar to that characteristic of the electron–phonon ef…