Materials Literature
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The high pressure behaviour of 3R-NbS2 has been investigated by angle-dispersive X-ray powder diffraction using diamond anvil cells up to 14 GPa. The compression behaviour of the structure is highly anisotropic. The compressibility perpendicular to the layers is 2.5 times higher than within the layers. A fit of a 3rd-…
We construct and apply an exchange-correlation functional for the one-dimensional Hubbard model. This functional has built into it the Luttinger-liquid and Mott-insulator correlations, present in the Hubbard model, in the same way in which the usual {\it ab initio} local-density approximation (LDA) has built into it t…
Four theoretical approaches to calculate momentum densities of electron-positron annihilation pairs (MDAP) in crystalline solids are confronted with 3D densities reconstructed from two-dimensional angular correlation (2D-ACAR) data for copper, chromium, and yttrium. It is shown that the Bloch-modified ladder theory, i…
Strain anisotropy can be well accounted for by the dislocation model of lattice distortion. In a texture-free powder or polycrystal, or if all possible Burgers vectors are equally populated, the dislocation contrast factors are a linear function of the fourth-order invariants of the hkl indices. Using this relation th…
Laser-induced cavitation bubbles near a curved rigid boundary are observed experimentally using high-speed photography. An image theory is applied to obtain information on global bubble motion while a boundary integral method is employed to gain a more detailed understanding of the behaviour of a liquid jet that threa…
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The structural properties of ${\mathrm{LaCoO}}_{3}$ were studied by means of high-resolution neutron powder diffraction in the temperature range $5<~T<~1000\mathrm{K}.$ Changes of the ${\mathrm{Co}}^{+3}$ spin states in this temperature interval are shown to affect not only the unit-cell volume, as previously kn…
Gold nanoshells have been synthesized by reacting aqueous HAuCl4 solutions with solid templates such as silver nanoparticles. The morphology, void space, and wall thickness of these hollow nanostructures were all determined by the templates, which were completely converted into soluble species during the replacement r…
The dielectric properties, internal friction, and Young’s modulus of (1−x%) Pb(Mg1/3Nb2/3)O3−x%PbTiO3 (for x=13, 23, and 33) ceramics have been measured. A phase-transition-like internal friction peak associated with Young’s modulus softening has been observed at temperature TR–F, which can be attributed to the relaxo…
The spherulitic growth mechanism of lysozyme crystals from aqueous solutions was examined quantitatively by taking advantage of a “buffer zone” of liquid–liquid phase separation occurring in lysozyme aqueous solution. This buffer zone technique allows us to obtain constant concentrations in both liquid phases during t…
The adopted crystal structure of the $\mathrm{AB}{\mathrm{O}}_{3}$ perovskites is determined by the balance between the interaction of the semicore states of the A and B atoms and oxygen ions. Topological considerations show that the structural setup always stabilizes the cubic phase at large pressures, while small or…
Epitaxial SrBi2Nb2O9 thin films have been grown by pulsed-laser deposition on (110)Pt bottom electrode epitaxially grown on (110) SrTiO3 by dc sputtering. X-ray φ-scans and electron channeling patterns reveal the epitaxial growth of the (116) SrBi2Nb2O9/(110)Pt bilayers. The hysteresis loop, dielectric response, and c…
First-principles total-energy calculations on hexagonal-close-packed (hcp) and body-centered-tetragonal (bct) states of bulk elemental magnesium have been made with a full-potential electronic structure program with both the local-density approximation and the generalized gradient approximation. The unique paths [call…
We have characterized a diamond p-n junction by means of electron-beam-induced current (EBIC) and cathodoluminescence (CL). The diamond p-n junction was fabricated by growing a B-doped p-type layer and a P-doped n-type layer on the {111} diamond substrate by microwave plasma enhanced chemical vapor deposition. The cro…
We report energy dispersive x-ray diffraction studies on nanocrystalline hexagonal graphite samples (average grain size=12 nm) in a diamond-anvil cell to 65 GPa at room temperature. A structural phase transition to a hexagonal diamond phase beginning at 15 GPa is completed at 55 GPa, and is reversible on decompression…
Measurements of thermal conductivity $(\ensuremath{\kappa})$ vs temperature are reported for a series of ${\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{MnO}}_{3}(0<~x<~0.2)$ specimens. For the undoped $(x=0),$ G-type antiferromagnetic compound a large enhancement of $\ensuremath{\kappa}$ below the Ne…
Thin-film single-wall carbon nanotube (SWNT) composites synthesized by pulsed laser deposition (PLD) are reported. Ultrahard, transparent, pure-carbon, electrically insulating, amorphous diamond thin films were deposited by PLD as scratch-resistant, encapsulating matrices for disperse, electrically conductive mats of…
We have investigated the ferroelectric domain structure formed in a Sr0.61Ba0.39Nb2O6 single crystal by cooling the crystal through the Curie point. Imaging the etched surface structure using a scanning force microscope (SFM) in both the topographic mode and the piezoresponse mode revealed that a multidomain structure…
The ferroelectric and piezoelectric properties of (001) BiScO3–PbTiO3 epitaxial films were investigated. Epitaxial films 1 μm thick were grown by pulsed laser deposition using ceramic targets of (1−x)BiScO3–xPbTiO3 (x=0.5) at substrate temperatures of 700 °C on (100) SrRuO3/(100)LaAlO3 substrates. Well-saturated hyste…
In recent years the generation of optical harmonics in molecular systems has become an area of increasing interest for a number of reasons. First, many organic crystals and polymeric solids prove not only to have usefully large optical nonlinearities but also to be surprisingly robust and thermally stable. Consequentl…