Materials Literature
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We develop a mean-field theory of carrier-induced ferromagnetism in diluted magnetic semiconductors. Our approach represents an improvement over standard Ruderman-Kittel-Kesuya-Yosida model allowing spatial inhomogeneity of the system, free-carrier spin polarization, finite temperature, and free-carrier exchange and c…
Linear response methods applied to electron systems often display a level of accuracy which is notable when viewed in terms of the strengths of perturbing interactions. Neglect of higher response terms is in fact justifiable in many cases and it can be shown to stem from an intrinsic interference between atomic and el…
We show that electron-ion structure factors in fluid metallic systems can be well understood from an application of linear response in the electron system, combined with hard-sphere like correlation for the ionic component. In particular, we predict that electron-ion structure factors fall into two general classes, on…
We propose a novel ultrafast pulsed laser deposition (PLD) technique, which eliminates the well-known problem of contamination of the films produced by PLD with particulates ejected from the target. The method uses low energy, picosecond duration laser pulses delivered onto a target at rates of several tens of MHz and…
Density-functional theory (DFT) studies are performed to examine geometric and electronic properties of orthorhombic bulk ${\mathrm{V}}_{2}{\mathrm{O}}_{5}$ as well as of its (010) oriented surface. Electronic states, total energies, as well as atom forces (used to obtain equilibrium geometries) are computed with the…
Research on the magnetocaloric effect and its application for cooling near room temperature over the past few years has helped to move this phenomenon from a scientific curiosity to an emerging technology. Two of the most important advances include the demonstration which proved that it is possible to obtain significa…
Highly sulfonated polyaniline prepared via a synthetic scheme using leucoemeralding base (LEB−SPAN) has been studied using X-ray photoelectron spectroscopy (XPS). A sulfonation level ( S / N ratio) as high as 0.80 ± 0.10 has been revealed in XPS analysis, agreeing well with the element chemical analysis results (∼0.78…
A magnetic sheet made of Fe–Si–Al flakes was found to have excellent permeability and electromagnetic-interferences characteristics in a quasimicrowave band. The flakes prepared by attrition were embedded in a polymer with their planes lying parallel to the sheet plane. This sheet exhibits a peculiar dual dispersion i…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTCyclodextrin-Modified Gold Nanospheres. Host−Guest Interactions at Work to Control Colloidal PropertiesJian Liu, Sandra Mendoza, Esteban Román, Matthew J. Lynn, Renliang Xu, and Angel E. KaiferView Author Information Center for Supramolecular Science, Department of Che…
Modified SERS (surface-enhanced Raman scattering) substrates are based on self-assembled monolayers (SAMs) formed from compounds such as alkanethiols. Chain lengths ranging from ethanethiol to octadecanethiol were used to investigate properties of modified SERS substrates. These properties include determining the magn…
We study photoinduced electron transfer from derivatives of poly(p-phenylenevinylene) (PPV) and nanocrystals of cadmium selenide via photoluminescence (PL) quenching and photoinduced absorption (PIA) spectroscopy. Using size-dependent quantum confinement to vary the energy levels of the nanocrystal acceptors, and chem…
A first-order transition above the Curie temperature for ferromagnetic La(FexSi1−x)13 (x=0.86 and 0.88) compounds has been confirmed by applying a magnetic field. The magnetic state changes from the paramagnetic to the ferromagnetic state and the transition field increases with temperature, indicating an itinerant ele…
We report experimental and theoretical investigations on the pressure dependence of the Raman-active radial and tangential vibrational modes of single-wall carbon-nanotube bundles. Using 514.5-nm excitation, we find that the radial mode intensity disappears beyond 1.5 GPa, and the tangential mode intensity also drops…
The existence of the edge states of single-layered H-terminated graphitic ribbons predicted by Nakada et al. [Phys. Rev. B 54, 17 954 (1996)] has been confirmed by first-principles calculations within the framework of the local-density approximation and the pseudopotentials. The edge states in cases of stacked ribbons…
High temperature, solution phase reduction of cobalt chloride in the presence of stabilizing agents was employed to produce magnetic colloids (ferrofluids) of cobalt nanocrystals. We systematically synthesized and isolated nearly monodisperse nanocrystal samples ranging in size from 2 to 11 nm while maintaining better…
A novel layered Rb−Pd polyselenide has been synthesized by methanothermal reaction of Pd 2+ with Se x 2 - (from Se 2 - + Se) in the presence of Rb 2 CO 3 . Rb 2 [Pd(Se 4 ) 2 ]·Se 8 ( I ) reveals a unique structure with infinite [Pd(Se 4 ) 2 ] 2 - sheet polyanions acting as a host for neutral Se 8 rings. The black shin…
Dodecaphenylporphyrins with varying degrees of fluorination of the peripheral phenyl rings (F(x)()DPPs) were synthesized as model compounds for studying electronic effects in nonplanar porphyrins, and detailed electrochemical studies of the chloroiron(III) complexes of these compounds were undertaken. The series of po…
Molecular dynamics simulations of a Xe monolayer sliding on Ag(001) and Ag(111) are carried out in order to ascertain the microscopic origin of friction. For several values of the electronic contribution to the friction of individual Xe atoms, the intra-overlayer phonon dissipation is calculated as a function of the c…
An astonishingly broad application potential in biotechnology, biomimetics, and nanotechnology is revealed by studies on the structure, chemistry, biosynthesis, genetics, self-assembly, and function of supramolecular surface layers (S layers). These are monomolecular, crystalline assemblies of protein or glycoprotein…
Ab initio molecular orbital calculations have been used to study the effect of γ substituents (X = H, F, or CN) on the addition of 1-Y,3-X-disubstituted propyl radicals (Y = F or CN) to ethylene. It is found that, although the γ substituent (i.e. penultimate unit) can exert a significant effect on the stability of the…