Materials Literature
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Scanning tunneling spectroscopy (STS) measurements were made on surfaces of two different kinds of graphite samples, Kish graphite and highly oriented pyrolytic graphite (HOPG), at very low temperatures and in high magnetic fields. We observed a series of peaks in the tunnel spectra associated with Landau quantization…
Spin-density-functional theory (SDFT) is the most widely implemented and applied formulation of density-functional theory. However, it is still finding novel applications, and occasionally encounters unexpected problems. In this paper we first briefly describe a few of the latter, related to issues such as nonuniquene…
We report the realization of nanotube-based multiple quantum dots that are fully defined and controlled with electrostatic gates. Metallic top-gates are used to produce localized depletion regions in the underlying tubes; a pair of such depletion regions in a nanotube with ohmic contact electrodes defines the quantum…
A double hydrophilic block copolymer (DHBC) is used as a crystal-growth modifier for controlled self-assembly of complex and unusual calcite pancakes with multiple stacked and porous layers (see Figure), based on a polymer-directed crystallization mechanism. The results demonstrate that it is possible to manipulate th…
[structures: see text] Bacteriochlorins (tetrahydroporphyrins) are attractive for diverse photochemical applications owing to their strong absorption in the near-infrared spectral region, as exemplified by the bacterial photosynthetic pigment bacteriochlorophyll a, yet often are labile toward dehydrogenation to give t…
Proposed is a substantially simplified, Preisach-like model for characterization of hysteretic systems, in particular magnetic systems. The main idea is to replace a two-dimensional Preisach density with just two real functions, describing in a {\em unique way} the reversible and irreversible processes. As a byproduct…
From recent Hall effect measurements and angle-resolved photo-emission spectroscopy the interesting picture emerges of co-existing hole- and electron-like quasiparticle bands, both in electron- and hole-doped superconducting cuprates. We reflect on the idea that bosonic electron-hole pairs may be formed in the cuprate…
The 120\ifmmode^\circ\else\textdegree\fi{} ordered antiferromagnetic state of the Hubbard model on a triangular lattice presents an interesting case of $U$-controlled competing interactions and frustration. The spin stiffness is found to vanish at $U\ensuremath{\approx}6$ due to competing spin couplings generated at f…
SiC nanowires (NWs) reinforce SiC matrix composites with high efficiency. With the incorporation of ∼ 6 vol.-% randomly oriented single-crystal SiC NWs in the matrices, the fracture toughnesses and flexural strengths of the composites doubled. The composites (see Figure) were fabricated in situ by a new process based…
We report the writing of very high resolution tungsten containing dots in regular arrays by electron beam-induced deposition (EBID). The size averaged over 100 dots was 1.0 nm at fwhm. Because of the statistical spread in the dot size, large and small dots are present in the arrays, with the smallest having a diameter…
Crystalline hexagonal-shaped superstructures of calcium carbonate, synthesized in the presence of ammonia, are shown to be assembled by a three-dimensional oriented attachment of vaterite nanoparticles. This unusual crystallographic lock-in mechanism enables the formation of complicated rounded structures with a cryst…
A fully inorganic analogue of the nanostructured dye-sensitized solar cell is fabricated using an electrochemically grown n-ZnO/CdSe core–shell nanowire array (see Figure). Filling the voids between the nanowires with p-type wide-bandgap CuSCN by a solution-deposition technique leads to an extremely thin solar cell ex…
The effect of citric acid and 1,2-dihydroxybenzene 3,5-disulfonic acid (DHBDSA), as additives, on the crystallization of gypsum was studied under simulated conditions of the of phosphoric acid production. Calcium hydrogen phosphate and sulfuric acid were mixed with dilute phosphoric acid at 80 °C, and the turbidity of…
Abstract The chemical modification of maritime pine sapwood ( Pinus pinaster Soland) with 3-isocyanatopropyltriethoxysilane (IPTES) and its subsequent hydrolysis were investigated. The formation of urethane linkages after the carbamoylation reaction was confirmed by Fourier-transform infrared (FTIR) spectroscopy. The…
A micro-encoder based on higher-order diffracted light interference has been developed for use in high-precision positioning. It uses ±3-order diffracted beams to obtain interference fringes for displacement detection and provides six signal periods for moving the scale grating by one grating period (3.2 µm) without a…
Abstract Metal‐containing polymers are obtained by grafting commercial poly(4‐vinylpyridine) (average molecular weight 60000 or 160000) with a Ni II chromophore complex. The metal‐containing chromophore was obtained from a tridentate benzoylhydrazine ligand. Chromophore fragments were grafted onto the polymer by forma…
We made use of the Raman spectroscopy to investigate the mechanism of hydrogen adsorption on carbon materials. We have recorded the Raman active roto-vibrational $Q$ branch of adsorbed hydrogen at various temperatures and pressures and we have developed a qualitatively theoretical model for the interpretation of the s…
Porosity-induced birefringence in a GaP membrane is studied using a method based on the analysis of beats in unpolarized and polarized transmittance spectra as well as in angular dependence of optical spectra. Birefringence as high as n e − n o = 0.25 was measured in a porous GaP membrane with the degree of porosity c…
Diamonds containing nitrogen in different forms have been irradiated by $3\text{--}\mathrm{MeV}$ electrons or $^{60}\mathrm{Co}$ gamma photons and characterized by optical absorption (OA) and electron spin resonance (ESR). An unusually low production rate of vacancies $(V)$ and interstitials $(I)$ was observed in gamm…
Abstract The effect of Co doping on the magnetic and transport properties of La 0.7 Sr 0.3 Mn 1– x Co x O 3 (0 ≤ x ≤ 0.5) is investigated. The Co doping at Mn sites dilutes the double‐exchange interaction between Mn 3+ and Mn 4+ ions and changes the long‐range ferromagnetic (FM) order of La 0.7 Sr 0.3 MnO 3 (LSMO) to…