Materials Literature
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The elastic strain and stress fields and the elastic energy of the system composed of a crystalline epitaxial layer of finite thickness coherently grown on a bulk substrate are calculated, when the intrinsic stress-free lattice parameter of the layer is modulated along directions parallel to the substrate surface. Whe…
The electron density distribution in AgBr was investigated on the basis of X-ray intensity data collected by single crystal diffractometry. It was verified from difference Fourier map that the charge tends to accumulate in the intermediate region between the neighbouring unlike atoms. The origin of the extra charge on…
The crystal structure of [N (CH 3 ) 4 ] 2 ZnCl 4 was studied at three temperatures, 30, 60and 90°C, in the paraelectric phase and at 5.5°C in the ferroelectric phase by using theX-ray reflection data collected by an automatic four-circle diffractometer. The split-atom method and the significance test showed that the c…
Two phenomena are pointed out which, if observed, would testify that the superconductivity in the Bechgaard salts belongs to the triplet pairing: excitation of the spin waves in the radio-frequency fields and the superconductivity restoration in high enough magnetic fields H || b *.
Interpretations for the energies corresponding to the peaks in the reflectivity and the imaginary part (${\ensuremath{\epsilon}}_{2}$) of the complex dielectric constant (\ensuremath{\epsilon}=${\ensuremath{\epsilon}}_{1}$+i${\ensuremath{\epsilon}}_{2}$) have been sought successfully using Penn-like model calculations…
The electronic structure of ${\mathrm{Fe}}_{\mathrm{x}}$O (x\ensuremath{\simeq}0.95) has been studied by photoemission spectroscopy using synchrotron radiation. Fe 3d character in the valence band is found to extend over a wide energy range from the top of the valence band to the satellite region, \ensuremath{\sim}15…
Properties of the electrical resistance of a one-dimensional quasicrystal, whose structure is governed by the Fibonacci rule, are studied by means of the Landauer formula. In particular, it is shown that the growth of the resistance with sample length is bounded by a power law for certain energies. More specifically,…
The reconstructions observed on the annealed (111) surfaces of Si and Ge can be explained on the basis of a simple model of the surface energetics. The driving force for the Si 7\ifmmode\times\else\texttimes\fi{}7 reconstruction is the formation of dimer-row domain walls, which order in a triangular pattern for topolo…
The dynamical structure factor S(Q,\ensuremath{\omega}) and the vibrational density of states g(\ensuremath{\omega}) for amorphous silicon have been measured by neutron scattering methods. Computer simulations of S(Q,\ensuremath{\omega}), based on a 216-atom structural model, are in substantial agreement with experime…
We propose that all ${A}_{1\mathrm{\ensuremath{-}}x}$${B}_{x}$ glasses [where A (B) is a late (early) transition metal] are structurally isomorphic, chemically random alloys which store hydrogen in tetrahedral interstitial sites ${A}_{4\mathrm{\ensuremath{-}}n}$${B}_{n}$ (in decreasing order n=4,3,2,. . . ). The maxim…
We report on thermoelectric power measurements of ${\mathrm{TiS}}_{2}$ taken as a function of temperature. These were done on single crystals between 10 and 300 K and confirm previous conclusions, namely the dominance of ionized-impurity scattering at low temperature and acoustic-phonon scattering at higher temperatur…
Polymer-dispersed liquid crystal (PDLC) films are potentially useful in applications requiring electrically controllable light transmission. In these applications, both a high on-state transmittance and a strong off-state attenuation are often needed over a wide operating temperature range. These transmittance charact…
The problem of an electric field applied to an isotropic dielectric containing a crack is considered as far as induced distortions and mechanical stresses are concerned. Near-tip distortions occur when the crack contains a conducting fluid or the surfaces are lined by a conducting layer. Previous treatments of the pro…
We have studied phonon scattering by films of metals, nonmetals, and condensed gases, 2 A\r{} to ${10}^{4}$ A\r{} thick, deposited onto polished faces of Si crystals, through measurements of the thermal conductivity of these crystals in the boundary scattering regime, between 0.05 and 2.0 K. No evidence has been found…
Expressions are derived for the effective phonon deformation potentials of polycrystalline materials, based on the properties of tensor invariants and the Voigt–Reuss–Hill averages [Proc. Phys. Soc. London Sect. A 65, 349 (1952)]. These results, and similar ones for the elastic constants, are used to determine the eff…
A completely ab initio theoretical investigation of the rocksalt-rhombohedral structural phase transition of GeTe is described. Starting from an anharmonic lattice Hamiltonian, a model Hamiltonian that includes coupling of the order parameter to long-wavelength strain is constructed. The parameters appearing in the mo…
We present results for the band structure, charge density, and total-energy-related quantities such as equilibrium lattice constants, bulk moduli, and TO-phonon frequencies for a variety of different semiconducting materials, using a simple ab initio self-consistent linear combination of pseudo-atomic-orbital scheme (…
The present work employs the total-energy pseudopotential technique to calculate the relative stabilities at high pressures of the zinc-blende \ensuremath{\beta}-Sn, and rocksalt structures in the series of compounds BN, BP, and BAs. For compressed volumes these compounds are shown to favor the rocksalt phase over \en…
Accurate full-potential self-consistent linearized augmented-plane-wave (FLAPW) calculations have been carried out for hexagonal boron nitride. The resulting energy-band structure indicates that this material is an indirect-gap insulator and shows the existence of two unoccupied interlayer bands, similar to those foun…
On the basis of a simple functional scaling, we have constructed the direct generalization of the Carnahan–Starling equation for the free energy of a hard sphere fluid to a nematic liquid crystal. The orientational degrees of freedom are completely decoupled from translational ones under that scaling, which is equival…