Materials Literature
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We report the observation of visible-light emission at room temperature from high fluence (0.3–3×1017 cm−2) Si+ implanted thermal SiO2 layers grown on silicon substrates. Significant blue-light emission and an intense broad luminescent band with a peak beyond 750 nm are observed after annealing at high temperature (T≥…
Ab initio calculations of structural and electronic properties of the C(001)-(2 \ifmmode\times\else\texttimes\fi{} 1) diamond surface are reported and discussed in direct comparison with Si(001) and Ge(001). Our results strongly favor a symmetric dimer reconstruction of C(001)-(2 \ifmmode\times\else\texttimes\fi{} 1)…
The large interest in the properties of transition metal surfaces has been recently fostered by inelastic helium atom scattering experiments carried out by Hulpke and Luedecke. Sharp and giant anomalies in the surface phonon dispersion curves along Gamma-H and Gamma-S have been detected on W(110) and Mo(110) at a cove…
We study a new hypothetical form of solid carbon \csc, with a unit cell which is composed of the \cs \ fullerene cluster and an additional single carbon atom arranged in the zincblende structure. Using {\it ab initio} calculations, we show that this new form of solid carbon has lower energy than hyperdiamond, the rece…
The electric conductivity of yttrium-stabilized zirconia exhibits a maximum as a function of dopant (Y 3+ ) cation concentration in isothermal and isobaric conditions. In order to improve the conductivity of this important solid electrolyte, it is essential to understand the ion transport mechanisms at the molecular l…
A magnetic field is found to have strong effects on the electronic structure and bulk properties of carbon nanotubes. A field-induced metal-insulator transition is predicted for all pure nanotubes. In a weak field, nanotubes exhibit both large diamagnetic and paramagnetic responses depending on the field direction, th…
This Letter discusses the possibility of realizing half-metallic antiferromagnets, i.e., systems with 100% spin polarization of the conduction electrons without showing a net magnetization. The predictions are based on electronic structure calculations using the local density approximation.
We present a novel experimental method to measure linear viscoelastic moduli of complex fluids using dynamic light scattering. A generalized Langevin equation is used to relate the mean square displacement of a probe particle to the storage and loss moduli of the bulk complex fluid. We confirm the experimental validit…
We have used ion beam analysis and scanning near-field optical microscopy to characterize the three-dimensional domain structure of a thin film of a phase-separating polymer mixture. In the initially mixed film, there first occurs coverage of one of its surfaces by an unbroken layer of one phase; between this "wet" su…
The spatial coherence properties of a monochromatic component of synchrotron radiation from an insertion device in the Fraunhofer limit are analyzed in the general case when the coherence distance is comparable with the beam width, expressing them by simple products and convolutions of Fourier transforms and autocorre…
A neutral templating route for preparing mesoporous molecular sieves is demonstrated based on hydrogen-bonding interactions and self-assembly between neutral primary amine micelles (S degrees ) and neutral inorganic precursors (l degrees ). The S degrees l degrees templating pathway produces ordered mesoporous materia…
A red cathode-ray phosphor, Y2OS:Eu3, shows a large decrease in luminescence efficiency at high excitation density at room temperature. The luminescence intensity is approximately proportional to the square root of the electron-beam current, indicating that a bimolecular-type nonradiative process competes with a radia…
Small-radius Frenkel excitons coupled with phonons can have diverse configurational structures depending on the symmetry of the electronic states involved and that of the associated modes of the inter-ionic/molecular vibrations. It is considered here that the symmetric excitons arise from the coupling with symmetry-re…
The theory for the stability of the nematic phase of parallel cylinders due to Mulder [Phys. Rev. A 35, 3095 (1987)] is generalized to binary mixtures. It is shown that adding cylinders of a different length to a one-component nematic phase of cylinders postpones the nematic–smectic A transition, enhancing the range o…
The model framework - group interaction modelling (GIM), thermal energy, model parameters, discussion - energy levels as states of matter polymer properties below the glass transition - volumetric properties, mechanical properties - viscoelasticity, failure initiation conditions, strain and time dependent mechanical p…
Abstract Polypropylene multifilament yarn samples were irradiated by gamma rays in air. The effect of radiation dose on thermal, structural, and mechanical properties was studied. Melting endotherms and crystallization exotherms gave useful information regarding the structural changes. X‐ray diffraction, infrared spec…
Photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy carried out on bulk samples of Er2S3-doped Ge33As12Se55 glasses demonstrate that Er3+ is incorporated in optically active sites in the glass and gives rise to a broad ∼1500–1600 nm 4I13/2→4I15/2 PL spectrum similar to those observed in Er-doped…
Electroluminescent devices were fabricated in SiO2 films containing Ge nanocrystals formed by ion implantation and precipitation during annealing at 900 °C, and the visible room-temperature electroluminescence and photoluminescence spectra were found to be broadly similar. The electroluminescent devices have an onset…
Computer simulations of the two (100) surfaces of cubic SrTi${\mathrm{O}}_{3}$ show that the top layer of the SrO-terminated surface reconstructs to a ferroelectric-monolayer phase while the Ti${\mathrm{O}}_{2}$-terminated surface remains bulklike. This behavior is shown to arise from a delicate crystal-environment se…
Electrical transports in the La 1-x Sr x FeO 3 system (0.05<or=x<or=0.3) was investigated as a function of temperature from 80 K to 350 K by dielectric properties, DC and AC conductivities. Two dielectric relaxation peaks appeared and their relative peak heights were closely related to the amount of Sr. The intensitie…