Materials Literature
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Spectrum of excitons in double-quantum-well structures is calculated in tilted magnetic field. It is shown that spectrum becomes asymmetric in quasimomentum if a transverse in respect to growth direction component of magnetic field is nonzero. A transition from $k$-space direct exciton ground state to $k$-space indire…
This Letter reports an experimental study of the dynamics of granular materials when vibrated horizontally. Convective motion is observed over wide range of parameters, similarly to the known effect observed under vertical vibration. However, under horizontal vibration we observe a striking novel effect on the oscilla…
Residual structure in the denatured state of a protein may contain clues about the early events in folding. We have simulated by molecular dynamics the denatured state of barnase, which has been studied by NMR spectroscopy. An ensemble of 10(4) structures was generated after 2 ns of unfolding and following for a furth…
The lattice vibrational spectra of the spinel phases, (x = 0, 0.33) and (y = 0.1, 0.3) (space group , have been measured as a function of temperature and composition by neutron inelastic scattering. Calculations of phonon densities of states (PDOSs) using interatomic potentials were performed and compared with the exp…
Nanometer sized CdS particles can be formed by exposing cadmium arachidate Langmuir-Blodgett films to hydrogen sulphide environment. X-ray scattering studies were performed to understand the formation of these particles that exhibit the quantum confinement effect in band structure. It was observed that the CdS layers…
As part of a study of species important in automotive exhaust chemistry, the reactivity of atomic N and NO on Pt(335) at low temperature has been studied. The atomic N was produced by dissociating adsorbed NO with a 76 eV electron beam. Cross sections for electron-stimulated desorption and dissociation are estimated f…
The nonlinear optical responses of laser-ablated Si nanoclusters were measured at λ=532 nm. Re{χ(3)} values as high as −(1.33±0.33)×10−3 esu were measured for films that were only 200 nm thick. The response time for this nonlinearity was as short as 3.5±0.5 ns, limited by our laser pulse duration.
A new type of dielectric resonance has been observed in several mixed ferroelectrics, ${\mathrm{KTa}}_{1\ensuremath{-}x}{\mathrm{Nb}}_{x}{\mathrm{O}}_{3}$ (KTN), ${\mathrm{K}}_{1\ensuremath{-}x}{\mathrm{Li}}_{x}{\mathrm{TaO}}_{3}$ (KLT), and ${\mathrm{PbMg}}_{1/3}{\mathrm{Nb}}_{2/3}{\mathrm{O}}_{3}$ (PMN), also known…
Broadband dielectric spectroscopy (10−2–1.8×109 Hz) is employed to study the molecular dynamics of the glass-forming hydrogen-bonded liquid propanediol confined to mesoporous M41S silica materials having two different topologies. It is shown that the dynamic glass transition takes place in the mesoporous system (diame…
Electron field emission from an array of micro-patterned monolithic diamond tips with varying sp2 content has been systematically investigated. The experimental results show that the field emission characteristics can be improved and the turn-on electric field can be reduced more than 50% by increasing sp2 content. Tw…
Synchrotron x-ray diffraction study establishes a novel structure sequence in ${\mathrm{SnI}}_{4}$ at high pressures to 153 GPa. A new crystalline phase responsible for the metallization is observed above 7.2 GPa. The pressure-amorphized ${\mathrm{SnI}}_{4}$ emerging above 15 GPa crystallizes at 61 GPa into another ne…
The thermal stability of amorphous hard carbon films produced by cathodic arc deposition was studied by near edge x-ray absorption fine structure (NEXAFS) spectroscopy, Raman spectroscopy, and nanoindentation evaluation. Pure carbon films of up to 85% sp3 content were deposited using a pulsed biasing technique and ann…
Europium activated yttrium oxide (Eu:Y2O3) phosphor films have been grown in situ on (100) bare and diamond-coated silicon substrates using a pulsed laser deposition technique. Diamond-coated silicon substrates were prepared using hot filament chemical vapor deposition of diamond onto silicon. Photoluminescence bright…
The results of simultaneous time-resolved measurements of dielectric relaxation and x-ray scattering during isothermal crystallization from the glassy state of poly(ethylene terephthalate) are reported. We find a dynamical transition in the early stage of crystallization. The $\ensuremath{\alpha}$-relaxation process,…
Diffractive gratings with period varied by an electric field are developed using a cholesteric liquid crystal confined between two transparent electrodes with unidirectionally treated alignment layers. In the initial state (zero field), the cholesteric layers are parallel to the cell planes. The electric field creates…
Phonon spectra for epitaxial monolayer films of hexagonal boron nitride $(h\ensuremath{-}\mathrm{BN})$ on Ni, Pd, and Pt (111) have been measured for the first time by using high resolution electron energy loss spectroscopy. On Ni(111), we have found two remarkable features in the observed dispersion curves: a level s…
Exact analytical results are obtained for the flux-pinning-induced magnetostriction in cylindrical type-II superconductors placed in parallel magnetic field. New modes of irreversible deformation are found: In contrast to the circular cylinder where shape is conserved, it is shown that a square cross-section deforms w…
The controlled synthesis of PbSe nanocrystal quantum dots with narrow size distributions was achieved through phase decomposition of the PbSe solid solution in a phosphate glass host. Structural characterization by electron microscopy and x-ray diffraction shows that the dots have mean diameters between 2 and 15 nm. T…
We construct a theory of the dielectric properties of a polymer dispersed liquid crystal droplet film containing bipolar droplets whose principal axes respond to an electric field. The theory involves a balance of an elastic energy term favouring an initial zero-field distribution of droplet axes and a dielectric ener…
This paper presents results of a study of the barrier effect in solid dielectrics in uniform and highly inhomogeneous electric fields. The influences of various factors such as mechanical strain, the position of the barrier in gap, space charge, the permittivity and the conductivity gradient both on the breakdown volt…