Materials Literature
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We present a systematic study on the structural and electronic properties of all alloy configurations of BexZn1−xO in a unit cell with 16 cations using density functional theory (DFT) methods. The 216 complexity is reduced by considering the symmetry of the parent structures. The experimental structures and electronic…
Optically stimulated luminescence (OSL) and thermoluminescence (TL) measurements were performed on polycrystalline NaMgF3:Eu2+ as well as sintered and quenched NaMgF3:Eu2+ after exposure to ionizing radiation. The authors find a range of TL traps and the sintering and quenching process reduces the concentration of sha…
We herein report the dispersion of multi-walled carbon nanotubes (MWCNTs) using trifluoroacetic acid (TFA) as a co-solvent. TFA is a strong but volatile acid which is miscible with many commonly used organic solvents. Our study demonstrates that MWCNTs can be effectively purified and readily dispersed in a range of or…
The authors have studied the origin of nanostructure formation on diamondlike carbon film in femtosecond laser ablation at low fluence. Using the thin film target patterned with submicrometer-size stripes, they have observed that the nanostructure starts to be formed on the crest of stripes along the direction perpend…
Gelling together: Merocyanine dyes possessing a cholesterol group as a gel-forming auxiliary self-assemble into nanoscopic fibers in apolar cyclohexane and polar acetone to form organogels, showing dramatically distinct optical properties through exciton coupling. This dramatic change is a result of different chromoph…
Double ferroelectric hysteresis (P-E) loops are observed in aged BiFeO3 multiferroic ceramic at room temperature and are explained according to an aging effect driven by charged defects with high activation energy. The aged BiFeO3 shows R3c defect symmetry and allows a nonzero charged defect-induced polarization (PD)…
The aim of this study is to establish the structure-properties relationship of tetrathiafulvalene (TTF). After this study (1) TTF crystals with α and β phases were controllably obtained by the cast method with careful selection of the solvents, and (2) organic field-effect transistors (OFETs) of α and β phases both ex…
Catalytic properties of metal nanoparticles toward gas-phase carbon nanotube (CNT) growth are presented. Narrow dispersions of iron (Fe) and nickel (Ni) nanoparticles are prepared in a direct current microplasma reactor and subsequently introduced with acetylene (C2H2) and hydrogen (H2) into a heated flow furnace to c…
Inelastic neutron scattering measurements on thermoelectric Zn4Sb3 reveal a dominant soft local phonon mode at 5.3(1) meV. The form factor of this local mode is characteristic for dumbbells vibrating preferably along the dumbbell axis and can be related to a vibration of Sb dimers along the c axis. The Lorentzian widt…
A unique core–shell structure was observed in coarse grains in (K,Na)NbO 3 (KNN)‐based lead‐free piezoelectric ceramics. It is morphologically different from the chemical inhomogeneity‐induced core–shell grain structure reported previously in BaTiO 3 ‐based ceramics. The core region is composed of highly parallel nano…
The thermal conductivity of single-wall carbon nanotubes (SWCNTs) is predicted to increase with length, but this has never been proved experimentally because of limitations in previous measurement methods. Here, the authors report the measurement of the length-dependent thermal conductivities of individual SWCNTs on a…
We investigate the importance of quantum orbital fluctuations in the orthorhombic and monoclinic phases of the Mott insulators LaVO(3) and YVO(3). First, we construct ab initio material-specific t(2g) Hubbard models. Then, by using dynamical mean-field theory, we calculate the spectral matrix as a function of temperat…
Upconversion nanocrystals (NCs) of NaYF4:Yb,Ln (Ln=Er and Tm) in cubic and hexagonal phases were synthesized in oleic acid (OA) and/or trioctylphosphine (TOP) with octadecene (ODE) via a thermolysis method. Only cubic-phase NCs were obtained in OA/ODE and TOP/ODE solvents; on the other hand, the hexagonal-phase NCs re…
A continuum theory is used to predict scaling laws for the morphological relaxation of crystal surfaces in two independent space dimensions. The goal is to unify previously disconnected experimental observations of decaying surface profiles. The continuum description is derived from the motion of interacting atomic st…
Highly ordered periodic arrays of silver nanoparticles have been fabricated which exhibit surface plasmon resonances in the visible spectrum. We demonstrate the ability of these structures to alter the fluorescence properties of vicinal dye molecules by providing an additional radiative decay channel. Using fluorescen…
In a previous paper (Phase Transitions, 80(9), 987, 2007) we discussed the smectic and nematic textures of some mesomorphic oxadiazole compounds with terminal Cl-substituent. Optical microscope investigations showed a very interesting behaviour of smectic and nematic phases; the smectic phase has fan-shaped and toric…
We consider a graphene sheet folded in an arbitrary geometry, compact or with nanotube-like open boundaries. In the continuous limit, the Hamiltonian takes the form of the Dirac operator, which provides a good description of the low energy spectrum of the lattice system. We derive an index theorem that relates the zer…
We treat the spin injection and extraction via a ferromagnetic metal/semiconductor Schottky barrier as a quantum scattering problem. This enables the theory to explain a number of phenomena involving spin-dependent current through the Schottky barrier, especially the counter-intuitive spin polarization direction in th…
We calculate the temperature dependence of NMR relaxation rate and electrical resistivity for coupling to a local, strongly anharmonic phonon mode. We argue that the two-phonon Raman process is dominating NMR relaxation. Due to the strong anharmonicity of the phonon an unusual temperature dependence is found having a…
Starting from a detailed model for the kinetics of a step edge or island boundary, we derive a Gibbs-Thomson type formula and the associated step stiffness as a function of the step edge orientation angle, $theta$. Basic ingredients of the model are: (i) the diffusion of point defects (``adatoms'') on terraces and alo…