Materials Literature
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We consider a tight-binding Hamiltonian defined on the quasiperiodic Ammann-Beenker tiling. Although the density of states (DOS) is rather spiky, the integrated DOS is quite smooth and can be used to perform spectral unfolding. The effect of unfolding on the integrated level-spacing distribution is investigated for va…
The absorptive and emissive behavior of four highly fluorescent bisalkyl-substituted poly( p- phenyleneethynylenes) (R = hexyl, dodecyl, 2-(ethyl)hexyl, and 3,5,5-trimethylhexyl) was examined. Aggregate and excimer formation was seen in solution and in the solid state by a combination of absorption and fluorescence sp…
Sp3-hybridized semiconductors (including InP, GaAs, CdSe, and Si) are remarkable from the perspective of physical chemistry. A single electron created by HOMO-LUMO promotion moves rapidly in response to an applied
Three generations of ester-terminated dendrimers have been constructed from (1 R,2 S )-2-amino-1-phenyl-1,3-propanediol, 1, as the central core. The chiroptical properties of the dendrimers were measured revealing that the molar rotations [Φ] of the dendrimers decreased with increasing dendrimer generation. Comparison…
19 F NMR measurements on lithium perfluorononanoate [LiPFN] in D 2 O and in solutions of D 2 O with poly(vinylpyrrolidone) [PVP] at different molecular weights have been carried out. A careful study of literature data and COSY maps allowed the full assignment of the 19 F resonances as a function of concentration and c…
The ion pair charge-transfer (IPCT) complexes (C(14)H(12)N(2))[Cu(opba)].3H(2)O (1) and Na(2)(C(12)H(12)N(2))[Cu(opba)](2).4H(2)O (2), opba = o-phenylenebis(oxamate), have been isolated. Both compounds crystallize in the triclinic space group P&onemacr;. Crystal data for the compounds 1, a = 7.3216(13) Å, b = 10.1756(…
Hollow microspheres of titanium dioxide have been prepared by spray-drying a colloidal suspension of an exfoliated titanate followed by heating above 400 °C. The individual hollow sphere with a diameter of tens of micrometers is characterized by its extremely thin crust, tens of nanometers thick. Because 99% of the pa…
The structure of AgCl formed in the course of chlorine adsorption on Ag(111) surface was studied by STM. For the first time atomic resolution STM images of silver chloride were obtained. The silver chloride was detected as small (30-60 A in diameter) islands located on the atomic terraces. The upper plane of the islan…
We study the influence of implantation parameters (temperature, implanted dose, and current density) on the microstructure of carbon onions produced by carbon ion implantation into silver substrates held at elevated temperature. Carbon onions are synthesized only for temperatures higher than 400 °C. An increase of the…
We have studied n-type silicon containing gold and gold–hydrogen complexes using high-resolution “Laplace” deep-level transient spectroscopy. This technique has enabled two quite distinct electron emission rates to be observed at temperatures between 240 and 300 K. These are associated with the gold acceptor and the l…
We report an optical reflectivity study of charge and spin ordering in ${\mathrm{Bi}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ ( $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.74$ and 0.82) single crystals. In the high temperature phase, $T>{T}_{\mathrm{co}}$, which is characterized by ferroma…
The first study of thermal conductivity, $\ensuremath{\kappa}$, in a quasi-two-dimensional organic superconductor of the $\ensuremath{\kappa}\ensuremath{-}(\mathrm{BEDT}\ensuremath{-}\mathrm{TTF}{)}_{2}X$ family reveals features analogous to those already observed in the cuprates. The onset of superconductivity is ass…
When we use a scanning electron microscope-molecular beam epitaxy system with a GaAs (111)A substrate that dramatically improves the flatness of the growing surface, it makes possible detailed observations of the near-equilibrium growth processes of island nucleation, coalescence, and step motion. These observations a…
Semiconductor quantum dots and wires are the subject of great interest, mainly due to their size-dependent electronic structures, in particular increased band gap and therefore optoelectronic properties. We have electrodeposited films of size-quantized CdS (∼4 to 5 nm cross section by 15 nm height) as a buffer layer o…
We have fabricated a self-organized chain of crystalline-silicon nanospheres via an extension of the vapor-liquid-solid mechanism. Transmission electron microscopy, electron energy-loss spectroscopy, and electron-induced x-ray fluorescence analyses have proved that the crystalline silicon nanospheres, of about 10 nm i…
The local magnetism and charge ordering of ${\mathrm{La}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{MnO}}_{3}$ was investigated between room temperature and 1.3 K by means of ${}^{139}\mathrm{La}$ and ${}^{55}\mathrm{Mn}$ NMR. Antiferromagnetic and ferromagnetic domains are assigned unambiguously to the insulating charge order…
The triboluminescence intensity from stress-activated Sr3Al2O6:Eu,Dy (SAO-ED) was so strong that we could see it with the naked eye in the atmosphere. The luminescence integrated intensity was about five hundred times as high as that of crystal sugar. We think that the light emission is due to the movement of dislocat…
A simple model to investigate the long time dynamics of glass formers is presented and applied to study a Lennard-Jones system in supercooled and glassy phases. According to our model, the point representing the system in the configurational phase space performs harmonic vibrations around (and activated jumps between)…
Europium-doped yttrium oxide (Eu:Y2O3) luminescent thin films have been grown in situ on single crystal (0001) sapphire substrates using a pulsed laser deposition technique. The films grown under different deposition conditions have been characterized using microstructural and luminescent measurements. The photolumine…
The measurement of misorientation angle distributions following different amounts of deformation in cold-rolled aluminum and nickel and compressed stainless steel is reported. The scaling of the dislocation cell boundary misorientation angle distributions is studied. Surprisingly, the distributions for the small to la…