Materials Literature
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We have carried out an ultrahigh-field cyclotron resonance study of n-type ${\mathrm{In}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ films, with Mn composition x ranging from 0% to 12%, grown on GaAs by low-temperature molecular-beam epitaxy. We observe that the electron cyclotron resonance peak shifts to lower f…
A type of metal-dielectric composites has been proposed that is characterized by a resonancelike behavior of the effective permeability ${\ensuremath{\mu}}_{\mathrm{eff}}$ in the infrared and visible spectral ranges. This material can be referred to as an optomagnetic medium. It consists of conducting inclusions in th…
The physics of a two-level system coupled to Ohmic bath is studied by means of the perturbation approach based on a unitary transformation. Our main results are: The coherence-incoherence transition is at $α_c={1\over 2}[1+Δ_r/ω_c]$; for $α<α_c$ the dynamical quantity $P(t)=\cos(ω_0 t)\exp(-γt)$; the sussceptibility $…
It has been observed that the effect of magnetic impurities in a superconductor is drastically different depending on whether the host superconductor is in a crystalline or an amorphous state. Based on the recent theory of Kim and Overhauser (KO), it is shown that as the system is getting disordered, the initial slope…
The stability of ${\mathrm{M}\mathrm{g}\mathrm{H}}_{2}$ has been studied up to 20 GPa using density-functional total-energy calculations. At ambient pressure $\ensuremath{\alpha}\mathrm{\text{\ensuremath{-}}}{\mathrm{M}\mathrm{g}\mathrm{H}}_{2}$ takes a ${\mathrm{T}\mathrm{i}\mathrm{O}}_{2}$-rutile-type structure. $\e…
We performed density-functional theory calculations in the local-density approximation of the structural, electronic, and optical properties of 4-$\mathrm{\AA{}}$-diameter single-walled carbon nanotubes. The calculated relaxed geometries show significant deviations from the ideal rolled graphene sheet configuration. W…
A theoretical investigation of the angular distributions of photoelectrons (ADP) ejected from fixed-in-space molecules or clusters having C2v symmetry is presented. The consideration is based on an expansion of the photoelectron wave functions in symmetry-adapted spherical harmonics. The ADP is derived for linearly po…
Two strong violet-blue luminescence emissions at 390 and 440 nm under excitation at room temperature have been observed in the ordered mesoporous zirconium oxide post-treated with phosphoric acid. The oxide was characterized by powder x-ray diffraction, nitrogen adsorption, diffuse reflectance UV-vis spectroscopy, x-r…
Nematic emulsions and polymer dispersed liquid crystals (PDLCs) are composite materials formed by micron-sized droplets of mesogenic molecules, which are embedded in fluid or solid matrices, respectively. Both systems can be switched from an opaque to a trasparent state by application of a suitable electric field. The…
The mean field theory proposed originally by Kubo and Ohata for manganites is generalized for a ferrimagnetic half-metal and applied to the magnetite. The relevance of both the double exchange interaction and the superexchange one for the spin ordering in the conducting B sublattice of magnetite is shown. The shortcom…
The phase behavior of a liquid-crystal forming model colloidal system containing hard rodlike and platelike particles is studied using the Parsons–Lee scaling [J. D. Parsons, Phys. Rev. A 19, 1225 (1979); S. D. Lee, J. Chem. Phys. 87, 4972 (1987)] of the Onsager theory. The rod and plate molecules are both modeled as…
The adsorption of hydrogen (deuterium) and oxygen on neutral platinum clusters has been investigated in a cluster beam experiment. The beam passes through two low-pressure reaction cells and the clusters, with and without adsorbed molecules, are detected by laser ionization and mass spectrometry. Both H2 and O2 adsorb…
In this letter, magnetization reversal is investigated in (Ga,Mn)As thin films using the magneto-optical Kerr effect. A Stoner–Wohlfart model, modified to take into account the existence of magnetic reversal discontinuities associated with nucleation and propagation phenomena allows us to estimate most of the characte…
The population change of the photoluminescence (PL) W center (or ${I}_{I}$ center) with 2-MeV electron irradiation in proton-implanted silicon crystal was observed to investigate the origin of the center. While a straightforward annihilation of the W centers formed by proton implantation with an increase of the electr…
The bonding of atomic oxygen to ferrous iron was studied using the Fe(OH)2 system as a model of the ferrous iron center. All lowest triple, quintet, and septet states of OFe(OH)2 were studied at the complete active-space self-consistent-field theory level augmented by multireference second-order-perturbation theory. I…
The structure and the shape of polymer droplets of nanoscopic size on ultrathin cylindrical fibers (with diameters in the range of nanometers) is investigated by Monte Carlo simulation of a coarse-grained bead-spring type model. The interaction between atoms in the solid nanocylinder and the effective monomers is assu…
We have studied the dynamical and structural properties of dense charge stabilized colloidal suspensions by a combination of small-angle neutron scattering (SANS), 3D dynamic light scattering (3DDLS) and diffusing wave spectroscopy (DWS). SANS and 3DDLS extend static and dynamic light scattering techniques to the regi…
The shock response of the aluminum alloy 7010-T6, induced by the technique of plate impact, has been investigated as a function of orientation to the loading axis to the rolling direction. Measurements of the Hugoniot elastic limit (HEL) and spall strength show that the material is stronger in the longitudinal orienta…
A new luminescent material, Sr3Al10SiO20:Eu2+, has been synthesized. The material exhibits an emission peak at 466 nm for the (Sr0.993Eu0.007)3Al10SiO20 and a CIE chromaticity of (x=0.145, y=0.124), with relative intensity of 60% of commercial phosphor BaMgAl10O17:Eu2+ under vaccum ultraviolet excitation.
Three important frontiers of ultrafast time-resolved macromolecular crystallography are presented: extension of this technique to other biological systems; further developments in the elucidation of mechanism through the analysis of time-dependent movies to extract the underlying, time-independent, intermediate struct…