Materials Literature
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Ab initio electronic structure studies of prototypical polar interfaces of wurtzite III-V nitrides show that large uniform electric fields exist in epitaxial nitride overlayers, due to the discontinuity across the interface of the macroscopic polarization of the constituent materials. Polarization fields forbid a stan…
The morphological stability of two-dimensional islands nucleated on a substrate during vacuum or vapour-phase atom deposition is investigated. Using simple scaling arguments, it is shown that, contrary to expectation, dendritic islands may be converted into compact ones by increasing the deposition rate, provided that…
The quantum-confined Stark effect in single cadmium selenide (CdSe) nanocrystallite quantum dots was studied. The electric field dependence of the single-dot spectrum is characterized by a highly polarizable excited state ( approximately 10(5) cubic angstroms, compared to typical molecular values of order 10 to 100 cu…
An ultrathin (0.7 nm x ~150 nm x ~150 nm) covalent grid consisting primarily of ~2.5-nm squares with ~1.5-nm square voids has been synthesized by two-dimensional cross-linking polymerization of lanthanum(III)bis [5,10,15,20-tetrakis(4-pyridyl)porphyrinate] anion with p -xylylene dibromide, constrained to proceed on a…
We have prepared and characterized photosensitized zinc oxide (ZnO) nanoclusters, dispersed in methanol, using carboxylated coumarin dyes for surface adsorption. Femtosecond time-resolved emission spectroscopy allows us to measure the photo-induced charge carrier injection rate constant from the adsorbed photosensitiz…
Chemical strategies for parallel preparation of nanocrystal based single electron devices and nanocrystal-patterned substrates are presented. The Langmuir-Blodgett technique is used for the preparation of ordered particle monolayers, which are incorporated in solid state capacitance devices. Single electron charging i…
Theoretical descriptions of the spectrum of electronic excitations in real metals have not yet reached a fully predictive, "first-principles" stage. In this paper we begin by presenting brief highlights of recent progress made in the evaluation of dynamical electronic response in metals. A comparison between calculate…
We investigate numerically the interaction of a stream of granular particles with a resting obstacle in two dimensions. For the case of high stream velocity we find that the force acting on the obstacle is proportional to the square of the stream velocity, the density and the obstacle size. This behavior is equivalent…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTAn On/Off Circular Dichroism Signal Reveals a pH Dependent Competition between a Cyclodextrin and a Polyelectrolyte for an Atropisomeric Aromatic GuestSung Yun Yang, Mark M. Green, Gerald Schultz, Salil K. Jha, and Axel H. E. MüllerView Author Information Herman F. Mar…
The condensation of diaminobenzenedithiol with sulfur monochloride leads to the chloride salt of the radical cation of 3,6-dichlorobenzo[1,2- d:4,5- d ‘]bis(1,2,3-dithiazole), dichloro-[BB-123-DTA][Cl], which can be reduced to neutral dichloro-[BB-123-DTA] with triphenylantimony. A similar condensation with selenium t…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSuperconductor-to-Insulator Transition in an Organic Metal Incorporating Magnetic Anions: λ-(BETS)2(FexGa1-x)Cl4 [BETS = bis(ethylenedithio)tetraselenafulvalene; x ≈ 0.55 and 0.43]Hayao Kobayashi, Akane Sato, Emiko Arai, Hiroki Akutsu, Akiko Kobayashi, and Patrick Cass…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTConvenient Preparation of Stable, Narrow-Dispersity, Gold Nanocrystals by Ligand Exchange ReactionsLeif O. Brown and James E. HutchisonView Author Information Department of Chemistry and Materials Science Institute University of Oregon, Eugene, Oregon 97403-1253 Cite t…
Many problems in computational magnetics involve computation of fields which decay within a skin depth $δ$, much smaller than the sample size $d$. We discuss here a novel perturbation method which exploits the smallness of $ε\equiv δ/ d$ and the asymptotic behavior of the solution in the exterior and interior of a sam…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
We present the results of a detailed inelastic neutron scattering study of the dynamics of the ferroelastic phase transition in ${\mathrm{Na}}_{2}{\mathrm{CO}}_{3}$. The driving instability is a transverse acoustic mode that softens over a plane of wave vectors, resulting in a continuous loss of long-range order, in a…
The electronic states and optical transition properties of silicon quantum-well layers embedded by ${\mathrm{SiO}}_{2}$ layers are studied by the empirical pseudopotential homojunction model. The energy bands, wave functions, and the optical transition matrix elements are obtained for layers of thickness from 1 to 6 n…
The structure of has been investigated by high-temperature neutron diffraction and molecular dynamics simulation. It was found that the apparent Mg - F bond contraction reported in previous work arises from large anisotropy in the distribution of ions. The cell parameter in the cubic phase is approximately 2% less tha…
Barium titanate powders were produced using either an amorphous hydrous Ti gel or anatase precursor in a barium hydroxide (Ba(OH) 2 ) solution via a hydrothermal technique in order to discern the nucleation and formation mechanisms of BaTiO 3 as a function of Ti precursor characteristics. Isothermal reaction of the am…
The sound velocity v s ( T ) and the electrical resistivity ρ( T ) of La 1- X Sr X MnO 3 (0.11≤ X ≤0.17) have been measured and anomalies in v s ( T ), which are related to the polaron-ordered phase centered at X =1/8, have been observed. The phase diagram between the polaron-ordering temperature T P and X has been de…
The ferroelastic and antiferroelectric transition (between phases called P and R) in samples, pure and doped with Mn (0 - 3.3 mol%), was investigated. The phase diagram was obtained from DTA tests. The doping resulted in lowering of the P - R phase transition temperature. The shift of the P - R phase transition temper…