Materials Literature
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By a cleaved-edge overgrowth method with molecular beam epitaxy and a (110) growth-interrupt-anneal, we have fabricated a GaAs quantum well exactly 30 monolayers thick bounded by atomically smooth AlGaAs hetero-interfaces without atomic roughness. Micro-photoluminescence imaging of this quantum well indeed shows spati…
Very efficient amplification of light-matter waves (polaritons), that are a superposition of cavity photons and excitons [1] has recently been reported[2-11]. The optical gain curve versus the pump power shows a threshold and then saturates to a maximum value[7,11]. Very recently it has been shown that this limit-valu…
The first complete ab initio zero-temperature ternary phase diagram is constructed from the calculated energies of the elemental, binary and ternary Ti-Zr-Ni phases; for this, the icosahedral i-TiZrNi quasicrystal phase is approximated by periodic structures of up to 123 atoms/unit cell, based on a decorated-tiling mo…
Electropolymerization of aniline in the presence of poly(acrylic acid) on Au electrodes yields a polyaniline/poly(acrylic acid) composite film, exhibiting reversible redox functions in aqueous solutions at pH = 7.0. In situ electrochemical-SPR measurements are used to identify the dynamics of swelling and shrinking of…
Titanium complexes of the tridentate aryloxide Me–L3− [H3(Me–L) = 2,6-bis(4,6-dimethylsalicyl)-4-tert-butylphenol] have been prepared. Reaction of TiCl4 with 1 equivalent of H3(Me–L) gave [Ti(Me–L)Cl]21. Recrystallization of 1 from THF resulted in formation of the THF adduct Ti(Me–L)Cl(THF)22. Treatment of 1 with [NEt…
In this paper we discuss some applications of the classical Gibbs adsorption equation to specific diffuse interface models that are based on conserved and non–conserved order parameters. Such models are natural examples of the general methodology developed by J. W. Gibbs in his treatment of the thermodynamics of surfa…
High quality ZnO films on α–Al2O3 (sapphire) have a great important application for optoelectronic devices in the future. This study investigated the influence of electric field on the atomic layer epitaxy of ZnO on the (0001) sapphire substrates. Theoretical analyses indicated that the polarization orientation and th…
We report a simulation on the formation of ordered stripe structures of nanoscale rods driven by symmetric diblock copolymer melts. Due to the preferential adsorption of one species of the diblock onto the mobile rods, the phase ordering process will couple with the movement of rods. We find that the self-assembly of…
The photolysis of aqueous ICN is studied by transient absorption spectroscopy covering the spectral range from 227 to 714 nm with 0.5 ps time resolution. The experimental data show that when ICN(aq) is photolyzed at 266 nm, it dissociates into I and CN and both the I(2P3/2) and I(2P1/2) channels are populated. Approxi…
The basis for the conjecture that water’s Tg may be 165±5 K [Velikov, Borick, and Angell, Science 294, 2335 (2001)] has been examined. It is shown that (i) differential scanning calorimetry (DSC) scans provided by Hallbrucker and Mayer [J. Phys. Chem. 91, 503 (1987)], and used as a basis for the conjecture, do not rep…
The bond valence method is applied to analyze local structure models from reverse Monte Carlo (RMC) fits to diffraction data. While our earlier studies demonstrated that for a wide range of silver ion conducting glasses both absolute value and activation energy of the ionic conductivity may be predicted from the volum…
Low-frequency Raman spectra are performed on silver nanocrystals self-organized on a hexagonal compact array on highly oriented pyrolytic graphite (HOPG) substrate. In addition to the well-known Raman scattering by the nanoparticle quadrupolar vibration mode, two lower intensity bands at larger frequency shifts are ob…
Unsymmetrically substituted tetraphenylporphyrins, including A2B2 and AA′B2 types can be synthesised by bromination of 5,15-diphenylporphyrins followed by palladium catalysed Suzuki coupling to arylboronic acids and esters. Unsymmetrically substituted triphenylporphyrins are also accessed via partial debromination in…
STM data show that gold exhibits homogeneous nucleation and growth on polycrystalline titania surfaces. When very small Au particles are exposed to ambient air at room-temperature rapid sintering occurs (∼20 nm) accompanied by Au migration to titania crystallite grain boundaries. This process is driven principally by…
Lithium diffusion in amorphous LiNbO3, synthesized by a sol–gel process, was investigated by temperature- and frequency-dependent 7Li NMR experiments. 7Li spin-lattice relaxation rates T−11 and 7Li nuclear magnetic resonance spectra, in particular line shapes and motional narrowing of the central line, were measured.…
Starting from the united atom model, we construct a coarse-grained model for a flexible polymer chain, in which some successive CH2 atoms are combined into an effective segment. To connect the coarse-grained model with the atomistic model, we propose a scheme to obtain the effective potentials acting between bonded an…
We have investigated the complexation of the luminescent Nd(3+), Eu(3+), Gd(3+), Tb(3+), Er(3+), and Yb(3+) ions by a polylysin dendrimer containing 21 amide groups in the interior and, in the periphery, 24 chromophoric dansyl units which show an intense fluorescence band in the visible region. Most of the experiments…
We report the epitaxial growth of CdCr2Se4, an n-type ferromagnetic semiconductor, on both GaAs and GaP(001) substrates, and describe the structural, magnetic and electronic properties. Magnetometry data confirm ferromagnetic order with a Curie temperature of 130 K, as in the bulk material. The magnetization exhibits…
In the ferromagnetic metallic state of the colossal magnetoresistive (CMR) manganite La1.2Sr1.8Mn2O7, the spin density distribution is essentially in agreement with the standard picture in which the unpaired electrons occupy the three t2g orbitals, dxy, dyz, and dxz. However we find a small spin density ~4% of the tot…
Ca$_3$Ru$_2$O$_7$ undergoes an antiferromagnetic transition at $T_{\text{N}}=56 $K, followed by a Mott-like (MI) transition at $T_{\text{MI}}=48$ K. This nonmetallic ground state, with a charge gap of 0.1 eV, is suppressed by a highly anisotropic metamagnetic transition that leads to a fully spin-polarized metallic st…