Materials Literature
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A possibility to realize an isotropic left handed material up to optical frequencies is theoretically investigated. The proposed homogeneous structure consists of dielectric spheres embedded randomly in a negative permittivity host medium. While the effective permittivity of the structure is negative over a wide frequ…
Using high-resolution atomic force microscopy, we have shown extremely high stability of linear ferroelectric domains in epitaxial PbZr0.2Ti0.8O3 thin films heated up to 735°C, a significant advantage for technological applications. An elevated transition temperature ∼785°C is observed even in relatively thick (91nm)…
In a contact-density chain-growth study we investigate the solubility-temperature pseudophase diagram of a lattice polymer in a cavity with an attractive surface. In addition to the main phases of adsorbed and desorbed conformations we find numerous subphases of collapsed and expanded structures.
Infrared (IR) spectroscopy, atomic force microscopy (AFM), and dielectric spectroscopy methods were employed to study structural and dynamic changes in the tannic acid (TA)-stabilized pericardium tissue. Chemically stabilized pericardium tissue is widely used in construction of the tissue derived bioprostheses. IR spe…
Samples made of an isotropically oriented ensemble of atomic clusters or structures that are not large crystals (i.e. extended less than 10 periods in each direction) are at the frontier of today's material science and chemistry. Examples are nanoparticles, nanotubes, amorphous matter, polymers, and macromolecules in…
In this article, we demonstrate that a subwavelength metal slit surrounded by dielectric surface gratings possesses a directional beaming effect. We propose a surface plasmon diffraction scheme to explain the three kinds of beaming conditions. The numerical simulations of the illustrative structures undertaken used a…
We have investigated the charge dynamics of ${\mathrm{VO}}_{2}$ by optical reflectivity measurements. Optical conductivity clearly shows a metal-insulator transition. In the metallic phase, a broad Drude-like structure is observed. On the other hand, in the insulating phase, a broad peak structure around $1.3\phantom{…
Metal-semiconductor core-shell nanostructures have been synthesized to explore the influence of metal nanostructures on the photoluminescence of semiconductors. Up to 40 times enhancement in the emission intensity was observed in the Au–CdS core-shell nanostructures. The mechanism where the excited electrons on Au sur…
ZnS nanowires with periodically alternating twins along the growth direction of wires have been synthesized via a thermal evaporation method. Structural characterizations reveal that both sphalerite (cubic) and wurtzite (hexagonal) phases coexist in the synthesized nanowires. The periodically twinned ZnS nanowires are…
High-level ab initio molecular-orbital methods have been employed to determine the relative stability among four neutral and anionic B20 isomers, particularly the double-ring tubular isomer versus three low-lying planar isomers. Calculations with the fourth-order Moller-Plessset perturbation theory [MP4(SDQ)] and Dunn…
Epitaxial BiFeO3 (BFO) thin films were fabricated on (001)-, (110)-, and (111)-oriented single-crystal SrRuO3(SRO)∕SrTiO3(STO) structures by chemical solution deposition. X-ray diffraction indicates the formation of an epitaxial single-phase perovskite structure and pole figure measurement confirms the cube-on-cube ep…
We measure nonlinear optical scattering from individual Au nanorods excited by ultrafast laser pulses on resonance with their longitudinal plasmon mode. Isolating single rods removes inhomogeneous broadening and allows the measurement of a large nonlinearity, much greater than that of nanorod ensembles. Surprisingly,…
A multiferroic heterostructure is constructed by growing an epitaxial piezoelectric $\mathrm{Pb}({\mathrm{Zr}}_{0.3},{\mathrm{Ti}}_{0.7}){\mathrm{O}}_{3}$ film on a magnetostrictive layered manganite single crystal of composition ${\mathrm{La}}_{1.2}{\mathrm{Sr}}_{1.8}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$. The efficient…
Measurements of the static magnetic susceptibility and of the nuclear magnetic resonance of multiwalled vanadium oxide nanotubes are reported. In this nanoscale magnet the structural low dimensionality and mixed valency of vanadium ions yield a complex temperature dependence of the static magnetization and the nuclear…
An important challenge in regenerative medicine is the design of suitable bioactive scaffold materials that can act as artificial extracellular matrices. We reported previously on a family of peptide-amphiphile (PA) molecules that self-assemble into high-aspect ratio nanofibers under physiological conditions, and can…
The optical response of porous silicon affinity biosensors depends strongly on their nanomorphology because the sensing species does not completely fill the pores but is instead attached to the pore walls. The performance and sensitivity of porous silicon microcavity biosensors are calculated as a function of pore siz…
Many-body Hamiltonians obtained from first principles generally include all possible non-local interactions. But in dynamical mean field theory the non-local interactions are ignored, and only the effects of the local interactions are taken into account. The truncation of the non-local interactions is a basis dependen…
In the present work we study experimentally the influence that the domain structure of a fer- romagnet (FM) has on the properties of a superconductor (SC) in bilayers and multilayers of La0.60Ca0.40MnO3/Nb and FePt/Nb proximity hybrids. Specific experimental protocols that were employed in the performed magnetization…
Eu 2 + -doped ternary nitride phosphor, Sr2Si5N8:Eu2+, was prepared by the carbothermal reduction and nitridation method. The Rietveld refinement analysis showed that the single phase products were obtained. Two main absorption bands were observed on the diffuse reflection spectra peaking at about 330 and 420nm, so th…
The carrier recombination processes in ZnO quantum dots ($\ensuremath{\sim}4\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ in diameter), ZnO nanocrystals ($\ensuremath{\sim}20\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ in diameter) and bulk ZnO crystal have been studied using photoluminescence (PL) spectroscopy in the temperatur…