Materials Literature
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We report on a study of pressure-dependent structural properties of LaAlO 3 , which is considered to be a model material of the class of `tilted' perovskites. Our high-pressure investigation by means of Raman spectroscopy and synchrotron radiation shows that LaAlO 3 presents structural instabilities under pressure and…
We have investigated the electronic structure of capped carbon nanotubes under electric fields by density functional calculations. The calculated effective work function of the capped armchair nanotubes decreases linearly with increasing electric fields, whereas that of the metal tip decreases quadratically. We analyz…
Using time-resolved photoluminescence measurements, the recombination rate in an In$_{0.18}$Ga$_{0.82}$N/GaN quantum well (QW) is shown to be greatly enhanced when spontaneous emission is resonantly coupled to a silver surface plasmon. The rate of enhanced spontaneous emission into the surface plasmon was as much as 9…
Taking into account both random impurity distribution and thermal fluctuations of localized spins, we have performed a model calculation for the carrier (hole) state in Ga$_{1-x}$Mn$_x$As by using the coherent potential approximation (CPA). The result reveals that a {\it p}-hole in the band tail of Ga$_{1-x}$Mn$_x$As…
In this communication we suggest a formulation of the optical conductivity as a convolution of an energy-resolved joint density of states and an energy-frequency labelled transition rate. Our final aim is to develop a scheme based on the augmented space recursion for random systems. In order to gain confidence in our…
Strained thin films of charge/orbital-ordered (CO/OO) Nd 0.5 Ca 0.5 MnO 3 with various thicknesses have been grown on (100) SrTiO 3 and (100) LaAlO 3 substrates, by using the pulsed laser deposition technique. The thickness of the films drastically influences the transport properties. As the thickness decreases, the C…
We have investigated electronic structures of a room-temperature-diluted magnetic semiconductor: Co-doped anatase ${\mathrm{TiO}}_{2}.$ We have obtained the half-metallic ground state in the local-spin-density approximation (LSDA) and the insulating ground state in the $\mathrm{LSDA}+U+\mathrm{SO}$ incorporating the s…
Physical properties of semiconducting ${\mathrm{CdF}}_{2}$ crystals doped with In are determined from measurements of the radio-frequency response of a sample with Schottky barriers at frequencies $10\ensuremath{-}{10}^{6} \mathrm{Hz}.$ The dielectric constant, the dc conductivity, the activation energy of the amphote…
Two-dimensional (2-D) ordered mesoporous silicas were synthesized following the literature synthesis procedures using two different silica sources (tetraethyl orthosilicate and sodium silicate) and poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) triblock copolymer template under acidic and neutral synt…
In this work, we report the synthesis of CdSe/CdS, CdSe/ZnS, and CdSe/ZnSe core/shell and CdSe/CdS alloy nanoparticles using bis(hexyl(methyl)dithio-/-diselenocarbamato)cadmium(II)/zinc(II) compounds as single-source precursors. We compare the optical properties of the core/shell nanoparticles in relation to those of…
Rodlike molecules form liquid crystalline phases with orientational order and positional disorder. The great majority of materials in which liquid crystalline phases have been observed comprise organic molecules or polymers, even though there has been continuing and growing interest in inorganic liquid crystals. Recen…
To explore the potential for use of ligand-conjugated nanocrystals to target cell surface receptors, ion channels, and transporters, we explored the ability of serotonin-labeled CdSe nanocrystals (SNACs) to interact with antidepressant-sensitive, human and Drosophila serotonin transporters (hSERT, dSERT) expressed in…
We develop an effective medium description of a two-dimensional photonic band-gap medium composed of dielectric cylinders of large dielectric constant. Using the transfer matrix method we have calculated reflection coefficients for a slab of the composite and plane-wave incidence, as well as the (complex) wavevector f…
The hardness of coarse-grained materials is inversely proportional to the square root of the grain size. But as Van Swygenhoven explains in her Perspective, at nanometer scale grain sizes this relation no longer holds. Atomistic simulations are providing key insights into the structural and mechanical properties of na…
Experiments, theory, and simulation were used to study glass formation in a simple model system composed of hard spheres with short-range attraction ("sticky hard spheres"). The experiments, using well-characterized colloids, revealed a reentrant glass transition line. Mode-coupling theory calculations and molecular d…
We have performed partitioned real-space density functional (PRDF) calculations of field evaporation of carbon clusters from single-walled carbon nanotubes (SWNT). The calculation results of the activation-energy barrier (AEB) for field evaporation of carbon clusters and hydrocarbon clusters from SWNT's show that the…
Static and dynamic surface interactions in deionized water were studied between poly(ethylene glycol) (PEG) and an opposed layer of either the same PEG or a highly charged cationic polymer, quaternized polyvinylpyridine (QPVP). The PEG, molecular weight 5000 g mol -1, was end-attached to hydrophobized mica by hydropho…
We report here a new technique of lithography in thin polyaniline film formed at the air−water interface, by simultaneous chemical and photochemical polymerization of aniline. A solution of aniline in acidic KBrO 3 /KBr polymerized to form thin film at the air−water interface. When the polymerization was carried out i…
The localized valence states characteristics of single-walled carbon nanotubes (SWNT's) are described by virtue of the discrete energy levels within first-principles calculations. We find that the contributions of the localized valence states to field emission are sensitively dependent on their spatial orientations an…
Temperature dependence of magnetic specific heat and magnetic susceptibility has been studied experimentally and theoretically in the semimagnetic semiconductor ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Te}$ for $x=0.024$ and $x=0.056,$ over the temperature range from 0.5 to 15 K, in magnetic fields up…