Materials Literature
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We describe a theory of Mn local-moment magnetization relaxation due to $p\ensuremath{-}d$ kinetic-exchange coupling with the itinerant-spin subsystem in the ferromagnetic semiconductor (Ga,Mn)As alloy. The theoretical Gilbert damping coefficient implied by this mechanism is calculated as a function of Mn-moment densi…
The formation energy, geometry, and electronic structure of isolated oxygen and aluminum vacancies in bulk and on the (0001) surface of corundum $(\ensuremath{\alpha}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3})$ have been investigated by means of periodic calculations in the framework of density functional theory…
Molecular dynamics simulations at 300 K in vacuum were used to study nanoparticle motion and structural changes during aggregation and coarsening of 3 nm sphalerite (ZnS) particles and atomic diffusion during the subsequent phase transformation. Interaction forces between atoms in different nanoparticles can induce tr…
Premature termination of growth, presumably because of catalyst deactivation, is an undesirable side effect of chemical vapor deposition of vertically aligned carbon nanotubes on predeposited metal catalyst films. The addition of ferrocene, an effective precursor for in situ Fe formation, was found to enhance carbon n…
Individual single-walled carbon nanotubes (SWNTs) produce highly bright images of the insulator surface around them when observed by scanning electron microscopy at low primary-electron voltage. We found that the insulator surface near SWNTs emits more secondary electrons due to electrons supplied through SWNTs connec…
Considering the three-phonon process, we calculate the thermal conductivity of zigzag tubes. It is found that thermal conductivity of an isolated (6, 0) single-walled carbon nanotube increases with the increase of temperature at low temperature, and would show a peak behavior at about 85 K before falling off at high t…
The electronic and magnetic structures of the ${\mathrm{LaMnO}}_{3}$ compound have been studied by means of periodic calculations within the framework of spin polarized hybrid density-functional theory. In order to quantify the role of approximations to electronic exchange and correlation three different hybrid functi…
The Mott transition in a quasi-two-dimensional organic conductor, $\ensuremath{\kappa}\ensuremath{-}(\mathrm{BEDT}\ensuremath{-}\mathrm{TTF}{)}_{2}\mathrm{Cu}[\mathrm{N}(\mathrm{CN}{)}_{2}]\mathrm{Cl}$ was investigated by resistance measurements under continuously controllable He gas pressure. We constructed the resis…
Nanostructured carbon films consisting of sp chains (polyynes and polycumulenes) embedded in an ${\mathrm{sp}}^{2}$ matrix are grown using supersonic carbon cluster beam deposition in ultrahigh vacuum at room temperature. All the specimens have been analyzed by in situ Raman spectroscopy. The use of different excitati…
We numerically obtain a quantitative demonstration that development of spatial correlations of mobility as temperature is lowered is responsible for the "decoupling" of transport properties of supercooled liquids. This result further demonstrates the necessity of a spatial description of the glass formation and theref…
A layered zinc hydroxide/surfactant composite was synthesized by pulsed-laser ablation of a metal Zn plate in an aqueous solution of the surfactant. The products were single-crystalline octagonal platelets with hexagonal crystal symmetry.
High quality luminescent CdS nanocrystals (NCs), with band edge emission tunable in the blue region of the visible spectrum, were synthesized by means of thermal decomposition of precursors with oleic acid as the surfactant and incorporated in optically transparent polystyrene (PS) and poly(methyl methacrylate) (PMMA)…
The transition from linear to nonlinear dynamical elasticity in rocks is of considerable interest in seismic wave propagation as well as in understanding the basic dynamical processes in consolidated granular materials. We have carried out a careful experimental investigation of this transition for Berea and Fontaineb…
High-energy (h$ν$ = 5.95 keV) synchrotron Photoemission spectroscopy (PES) is used to study bulk electronic structure of Na$_{0.35}$CoO$_{2}$.1.3H$_{2}$O, the layered superconductor. In contrast to 3-dimensional doped Co oxides, Co $\it{2p}$ core level spectra show well-separated Co$^{3+}$ and Co$^{4+}$ ions. Cluster…
We have studied the depth-dependent magnetic and structural properties of as-grown and optimally annealed ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ films using polarized neutron reflectometry. In addition to increasing the total magnetization, the annealing process was observed to produce a signif…
We present a theory of the collective orbital excitation termed orbital wave in perovskite titanates and vanadates with the triply degenerate ${t}_{2g}$ orbitals. The dispersion relations of the orbital waves for the orbital-ordered ${\mathrm{LaVO}}_{3},$ ${\mathrm{YVO}}_{3}$ and ${\mathrm{YTiO}}_{3}$ are examined in…
We have used scanning SQUID magnetometry to image vortices in ultra-thin [Ba$_{0.9}$Nd$_{0.1}$CuO$_{2+x}$]$_m$/[CaCuO$_2$]$_n$ (CBCO) high temperature superconductor samples, with as few as three superconducting CuO$_2$ planes. The Pearl lengths ($Λ= 2λ_{L}^2/d$, $λ_{L}$ the London penetration depth, $d$ the supercond…
Analytical Hartree-Fock gradients with respect to the cell parameter have been implemented in the electronic structure code CRYSTAL, for the case of three-dimensional periodicity. The code is based on Gaussian type orbitals, and the summation of the Coulomb energy is performed with the Ewald method. It is shown that a…
The kinetic behavior of a phase field model of electrochemistry is explored for advancing (electrodeposition) and receding (electrodissolution) conditions in one dimension. We previously described the equilibrium behavior of this model [J. E. Guyer, W. J. Boettinger, J. A. Warren, and G. B. McFadden, Phys. Rev. E 69,…
A diffuse interface (phase field) model for an electrochemical system is developed. We describe the minimal set of components needed to model an electrochemical interface and present a variational derivation of the governing equations. With a simple set of assumptions: mass and volume constraints, Poisson's equation,…