Materials Literature
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We report that the sign of the polarization of an epitaxial ferroelectric film can be determined from the interference between the x-ray scattering from the film and the substrate. X-ray scattering measurements of a 10 nm epitaxial PbTiO3 film grown by metal-organic chemical vapor deposition on a SrTiO3 substrate are…
Durch eine optimale Abstimmung der Donor‐Acceptor‐Stärken in heterocyclischen Methinfarbstoffen wie 1 kann der Cyaninzustand erreicht werden. Trotz nahezu verschwindender Polarisierbarkeiten zweiter Ordnung (β) setzt diese Chromophorklasse neue Maßstäbe für photorefraktive Anwendungen. Bereits bei einem Chromophorgeha…
It is argued that the model advanced by Lenef and Rand [Phys. Rev. B 53, 13 441 (1996)] for the nitrogen-vacancy center in diamond, exhibiting the 1.945-eV luminescence is incorrect. Lenef and Rand argue that the electronic ground state consists of two electrons occupying ${a}_{1}$ states localized on N and C, respect…
Für die Entwicklung von molekularen Schaltern sind Cobalt‐ und Mangankomplexe mit 1,2‐Benzochinon‐Liganden von großem Interesse. Diese Verbindungen haben elektronisch instabile Grundzustände, was zu Phänomenen wie gemischte Valenz, Spincrossover und Valenztautomerie führt. In jüngster Zeit wurde das elektronische Verh…
Absorption, emission, and excitation spectra of KMgF${}_{3}$ doped with Ce${}^{3+}$ have been measured in the near ultraviolet up to 180 nm. In this fluoroperovskite lattice, absorption of the Ce${}^{3+}$ impurity is found at energies higher than 4.4 eV. Broad-band emissions are measured at 350 nm and 275 nm which are…
Hydrothermally prepared zinc dihydroxy divanadate dihydrate crystallizes in the trigonal system (space group P\overline{3}m1). Its structure was solved ab initio from conventional X-ray powder data. Zn atoms occupy three of four octahedral sites in the close-packed layer of O atoms. These layers are connected by pyrov…
Abstract A large number of TADDOL (α,α,α′, α′‐ t etraaryl‐1,3‐ d ioxolan‐4,5‐ d imethan ol ) derivatives has been tested as chiral dopants for inducing conversion of nematic to cholesteric phases. With the Merck liquid‐crystal materials ZLI‐1695 and K15 , it was demonstrated that some TADDOLs have unprecedentedly high…
${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ exhibits as a function of temperature a metal-insulator transition (MIT) associated with a structural and a magnetic transition, which we have studied with x-ray-absorption measurements of ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ at the V $2p$ and O $1s$ edge as well as photoemission measu…
Higher order correlation functions as observed in four-dimensional NMR experiments on glass-forming liquids are interpreted in terms of a simple model for molecular reorientations. Its key assumption is an intrinsic link between the rotational and structural relaxation of the liquid. It is shown that the introduction…
We have studied the photoluminescence (PL) mechanism of crystalline Si single quantum wells sandwiched between ${\mathrm{SiO}}_{2}$ layers by site-selective excitation spectroscopy. The asymmetric PL spectrum is observed in the red spectral region at low temperatures and can be divided into two PL bands. The peak ener…
We have studied the electronic structure of ${\mathrm{CrO}}_{2}$ by photoemission spectroscopy and specific heat measurements. The Cr $3d$ band shows a splitting into the upper and lower Hubbard bands with a small but finite density of states at the Fermi level, consistent with its metallic behavior. The small renorma…
Macrophages were elicited by the subcutaneous implantation of ultra high molecular weight polyethylene (UHMWPE) for periods of 2, 7, and 14 days in rats. Exudates of varying volumes were produced that was comprised of granulocytes, monocytes, immature and mature macrophages, and T-lymphocytes. No B-lymphocytes were ob…
Iron monocarbide has been investigated between 12 000 and 18 100 cm−1 in a supersonic expansion by resonant two-photon ionization spectroscopy. Six new electronic states have been identified for which origins relative to the ground state have been determined. Three of these possess Ω′=3, one possesses Ω′=4, and two po…
The remarkably simple synthesis of tetrathia- and tetraoxarubyrins 1 and 2 is achieved by the routes presented here. Spectroscopic, 1H NMR, and electrochemical data suggest that 1, 2, and their protonated derivatives are aromatic 26 π electron systems, and the protonated derivatives form stable complexes in solution w…
The properties of sodiumnitroprusside (Na2[Fe(CN)5NO]*2H2O) are investigated by density functional theory. The calculated results both for the free anions as well as for the solid show that the ground-state Born–Oppenheimer surface has local minima for sidewards bonded and inverted NO. The calculated properties for th…
We present a method for simulating the chemical vapor deposition (CVD) of thin films. The model is based upon a three-dimensional representation of film growth on the atomic scale that incorporates the effects of surface atomic structure and morphology. Film growth is simulated on lattice. The temporal evolution of th…
A multiple-scattering formalism, based on the reflectivity matrix method of diffuse reflection high-energy electron diffraction (RHEED), is developed that allows us to calculate the electron-phonon scattering in RHEED due to correlated thermal vibrations for the case of one-phonon transitions. The scattering by the th…
Hyphoinycete assemblages, conidia in foam aiid thow prodticed o11 leal litter of three species (Plaruriua orirrifci l is. Populus riigrci aiid Srilix crtrociriereci), and reproductive activity oí the fungi colonizing leaves, were studied al four sites located in two Mediterranean inotintaiii streaiiis coiitraiting i n…
The global dynamics of polyisoprene (PI) in the controlled porous glass (CPG) Bioran have been studied with dielectric spectroscopy by varying the end-to-end vector (⟨ r 2 ⟩ 1/2 ) of the chain from dimensions smaller to much larger compared to the pore radius. Pulsed-field gradient NMR is used for the same systems and…
Magnetotransport properties of an 80 nm-thick high quality epitaxial film of SrRuO 3 grown on SrTiO 3 (001) were investigated. The film has tetragonal structural symmetry ( c -axis ⊥ film plane), and shows a uniaxial strong magnetic anisotropy with the easy axis along the c -axis. Magnetotransport phenomena are also u…