Materials Literature
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The adaptive kinetic Monte Carlo method uses minimum-mode following saddle point searches and harmonic transition state theory to model rare-event, state-to-state dynamics in chemical and material systems. The dynamical events can be complex, involve many atoms, and are not constrained to a grid-relaxing many of the l…
The intrinsic double helix conformation of the DNA strands is known to be the key ingredient of control of the electric current through the DNA by the perpendicular (gate) electric field. We show theoretically that Bloch oscillations in the DNA are also strongly affected by such lateral field; the oscillation frequenc…
We show that optical properties of linear molecular aggregates undergo drastic changes when aggregates are deposited on a metal surface. The dipole-dipole interactions of monomers with their images can result in strong {re-structuring of both the exciton band and the absorption spectrum, depending on the arrangement o…
We have demonstrated a method to disperse and exfoliate graphite to give graphene suspended in water-surfactant solutions. Optical characterisation of these suspensions allowed the partial optimisation of the dispersion process. Transmission electron microscopy showed the dispersed phase to consist of small graphitic…
Within the effective mass approximation and variational method the effect of dielectric constant mismatch between the size-quantized semiconductor sphere, coating and surrounding environment on impurity binding energy in both the absence and presence of a magnetic field is considered. The dependences of the binding en…
We theoretically compute the interface thermal resistance between crossing single walled carbon nanotubes of various chiralities, using an atomistic Green's function approach with semi-empirical potentials. The results are then used to model the thermal conductivity of three dimensional nanotube pellets in vacuum. For…
Water and silicon are chemically dissimilar substances with common physical properties. Their liquids display a temperature of maximum density, increased diffusivity on compression, they form tetrahedral crystals and tetrahedral amorphous phases. The common feature to water, silicon and carbon is the formation of tetr…
We theoretically demonstrated that all-angle negative refraction and imaging can be implemented by metallic nanowires embedded in a dielectric matrix. When the separation between the nanowires is much smaller than the incident wavelength, these structures can be characterized as indefinite media, whose effective permi…
BACKGROUND: There has been concern regarding risks from inhalation exposure to nanoparticles (NPs). The large number of particles requiring testing means that alternative approaches to animal testing are needed. OBJECTIVES: We set out to determine whether short-term in vitro assays that assess intrinsic oxidative stre…
Neutron diffraction measurements of a high-quality single crystal of ${\text{CaFe}}_{2}{\text{As}}_{2}$ are reported. A sharp transition was observed between the high-temperature tetragonal and low-temperature orthorhombic structures at ${T}_{S}=172.5\text{ }\text{K}$ (on cooling) and 173.5 K (on warming). Concomitant…
Today hydrogen peroxide is produced by an indirect process in which an alkyl anthraquinone is sequentially hydrogenated and oxidized. In this way hydrogen and oxygen are kept separate during the manufacturing process. A process where molecular oxygen is directly hydrogenated could be preferred if control of the sequen…
Detailed analysis of transport, magnetism, and x-ray absorption spectroscopy measurements on ultrathin ${\text{La}}_{0.7}{\text{Sr}}_{0.3}{\text{MnO}}_{3}$ films with thicknesses from 3 to 70 unit cells resulted in the identification of a lower critical thickness for a nonmetallic nonferromagnetic layer at the interfa…
Abstract A theoretical evaluation of the thermoelectric‐related electrical transport properties of 36 half‐Heusler (HH) compounds, selected from more than 100 HHs, is carried out in this paper. The electronic structures and electrical transport properties are studied using ab initio calculations and the Boltzmann tran…
In this paper, the reliability of tunable ferroelectric thin film capacitors has been addressed. The long term stability of tunable capacitors based on Ba0.3Sr0.7TiO3 films deposited by chemical solution deposition onto an alumina substrate was investigated by monitoring their tunable performance as a function of the…
We have investigated the interfacial and frequency dependent electrical properties of metal-ferroelectric-insulator-semiconductor capacitors with SrBi2Ta2O9 (SBT) ferroelectric films grown on ZrO2 buffer layer coated Si. Heterostructure SBT and ZrO2 thin films were deposited using rf magnetron sputtering. Interfacial…
The authors report on growth of ZnO nanoneedles (NNs) by metal organic chemical vapor deposition (MOCVD). Photoluminescence spectra of the NNs at 20 K are dominated by a surface excitonic (SX) emission at 3.367 eV. Temperature-dependent PL reveals the activation energies for the quenching of SX (∼11.2 meV) and donor b…
The nature of ferroelectric domain dynamics in polydomain epitaxial barium titanate thin film was investigated using the linear electro-optic effect. The dynamic response was studied as a function of bias field under pulsed excitation. Upon removal of the bias pulse a millisecond long transient response was observed t…
In the present work, the isothermal variation of the entropy (ΔST) for the compound Gd5Ge4 was studied at different applied hydrostatic pressures (from 0 up to 0.58 GPa). In all pressure ranges, we observe the giant magnetocaloric effect. The ΔST data for the compound Gd5Ge4 at zero applied pressure present two peaks:…
In this article, we analyze the dispersion features of cloaking structures formed by plasmonic materials and/or metamaterials. Following our recent proposal for realizing a cloaking metamaterial shell capable of drastically suppressing the total scattering of moderately-sized objects, we investigate the frequency resp…
We present a near edge x-ray absorption fine structure study of artificial chemical vapor deposition diamonds with sizes in the micron range and of size distributed nanodiamonds extracted from the Murchison meteorite. The modified peak shape in the case of the nanodiamond sample is explained by the interplay between t…