Materials Literature
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The linear combination of bulk bands method recently introduced by Wang, Franceschetti and Zunger [Phys. Rev. Lett.78, 2819 (1997)] is applied to a calculation of energy bands and optical constants of (GaAs)$_n$/(AlAs)$_n$ and (GaAs)$_n$/(vacuum)$_n$ (001) superlattices with n ranging from 4 to 20. Empirical pseudopot…
The mean-field theory represents a useful starting point for studying carrier-induced ferromagnetism in Mn$_x$III$_{1-x}$V diluted magnetic semiconductors. A detail description of these systems requires to include correlations in the many-body hole system. We discuss the effects of correlations among itinerant carrier…
A time-dependent global fiber-bundle model of fracture with continuous damage is formulated in terms of a set of coupled non-linear differential equations. A first integral of this set is analytically obtained. The time evolution of the system is studied by applying a discrete probabilistic method. Several results are…
Magnetization and magnetoresistance measurements are reported for antiferromagnetically coupled DyFe$_2$/YFe$_2$ multilayers in fields up to 23 T. We demonstrate that the formation of short exchange springs (~ 2 nm) in the magnetically soft YFe$_2$ layers results in a giant magneto-resistance as high as 32% in the spr…
We have studied thermodynamics of the Mg-B system with the modeling technique CALPHAD using a computerized optimization procedure. Temperature-composition, pressure-composition, and pressure-temperature phase diagrams under different conditions are obtained. The results provide helpful insights into appropriate proces…
We present a mean-field theory of carrier-induced ferromagnetism in Mn$_x$III$_{1-x}$V diluted magnetic semiconductors with a special emphasis placed on the magnetic anisotropy. The valence band holes are described using the six band Kohn-Luttinger model. We find that the magnetic anisotropy is a complicated function…
We present a tight-binding potential based on the moment expansion of the density of states, which includes up to the fifth moment. The potential is fitted to bcc and hcp Zr and it is applied to the computation of vibrational properties of bcc-Zr. In particular, we compute the isothermal elastic constants in the tempe…
For highly cross-linked polymer networks bonded to a solid surface, the effect of interfacial bond density and system size on interfacial fracture is studied using molecular dynamics simulations. Results for tensile and shear mode simulations are given. The correspondence between the stress−strain curve and the sequen…
The performance of several common approximations for the exchange-correlation kernel within time-dependent density-functional theory is tested for elementary excitations in the homogeneous electron gas. Although the adiabatic local-density approximation gives a reasonably good account of the plasmon dispersion, system…
Röhrenförmige molekulare Strukturen nehmen in der Natur verschiedenste biologische Funktionen wahr, erwähnt seien ihre Rolle beim Aufbau des Gerüsts der Mikrotubuli des Cytoskeletts, die Verpackungsfunktion viraler Hüllenproteine und ihre Funktion beim Transport von Molekülen sowie beim Screening von Transmembrankanäl…
The use of conjugated polymers for sensor applications continues to be the subject of intense research. In addition to their use as electronic conductors, they have been exploited as active sensing elements by coupling ligands to the backbone. In this approach, binding of an analyte results in physical distortions or…
The production of silica core-silver shell nanoparticles (silver nanoshells) by three different chemical methods is described. Each method produces a silver outer layer with a unique morphology, ranging from smooth and uniform, to rough on the 2−5 nm length scale, to spiky with extremely sharp, needlelike protrusions…
We show that a relatively simple approach for controlling the colloidal synthesis of anisotropic cadmium selenide semiconductor nanorods can be extended to the size-controlled preparation of magnetic cobalt nanorods as well as spherically shaped nanocrystals. This approach helps define a minimum feature set needed to…
Hollow tubular structures of molecular dimensions perform diverse biological functions in nature. Examples include scaffolding and packaging roles played by cytoskeletal microtubules and viral coat proteins, respectively, as well as the chemical transport and screening activities of membrane channels. In the preparati…
A series of zinc(II) and magnesium(II) alkoxides based upon a beta-diiminate ligand framework has been prepared. [(BDI-1)ZnO(i)Pr](2) [(BDI-1) = 2-((2,6-diisopropylphenyl)amido)-4-((2,6-diisopropylphenyl)imino)-2-pentene] exhibited the highest activity and stereoselectivity of the zinc complexes studied for the polyme…
Highly monodisperse CdSe nanocrystals were prepared in a three-component hexadecylamine-trioctylphosphine oxide-trioctylphosphine (HDA-TOPO-TOP) mixture. This modification of the conventional organometallic synthesis of CdSe nanocrystals in TOPO-TOP provides much better control over growth dynamics, resulting in the a…
Temperature dependence of resistivity in quasi-two-dimensional purple bronzes AMo6O17 (A=Na, K, and Tl) has been comparatively studied between 2 and 300 K at different magnetic fields. Huge positive magnetoresistance (MR) behavior below the Peierls transition temperature TP∼110 K was found in both K/Tl purple bronzes…
Peculiarities of the absorption saturation in doping superlattices with n-i-p-i crystal type structure are established. Calculations are performed in the k-selection rule model taking into account the screening of the electrostatic potential by current carriers and the density state tails.
Magnetoresistance of an insulating quasicrystalline AlPdRe film in large magnetic fields, Ralph Rosenbaum, Alexander Milner, Roland Haberkern, Peter Häussler, Eric Palm, Tim Murphy, Scott Hannahs, Bruce Brandt
Model polyurethane ionomer solution studies revealed that the critical parameters determining the solution behavior of ionomers are solvent polarity, solvent−backbone interactions, and ionic content of the ionomer. The three parameters are used to develop a novel ionomer solution diagram which provides a framework for…