Materials Literature
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Highly ordered arrays of nanosized GaAs-based dots were successfully prepared on GaAs (001) substrates by molecular-beam epitaxy using selected area growth. Selected area growth employed alumina nanochannel array (NCA) templates formed by anodic oxidation, bonded to the GaAs substrates. Homogeneous GaAs dots, as well…
Field electron emission behavior of individual multiwalled carbon nanotubes (MWNTs), that are elements of a vertically aligned array grown on a Si wafer, were analyzed with a scanning anode field emission microscope. The electron emission of each MWNT followed the conventional Fowler–Nordheim field emission mechanism…
The temperature and thickness dependence of permittivity of (Ba,Sr)TiO3 has been investigated. The films were deposited by liquid-source metalorganic chemical vapor deposition onto Pt/SiO2/Si, with thicknesses ranging from 15 to 580 nm. The dielectric response was measured from 100 to 520 K. As film thickness decrease…
The spin relaxation in the molecular magnet \Mn12 is investigated by a novel type of high-frequency magnetic spectroscopy. By reversing the external magnetic field the intensities of the $|\pm 10>\to |\pm 9>$ transitions within the ground multiplet redistribute; below $T\approx 2$ K resonant quantum tunneling is direc…
The magnetic behavior of single-crystal Ho$_2$PdSi$_3$, crystallizing in an AlB$_2$-derived hexagonal structure, is investigated by magnetic susceptibility ($χ$) and electrical resistivity ($ρ$) measurements along two directions. There is no dramatic anisotropy in the high temperature Curie-Weiss parameter or in the $…
We perform a systematic slave-boson mean-field analysis of the three-band model for cuprates with first-principle parameters. Contrary to widespread believe based on earlier mean-field computations low doping stripes have a linear density close to 1/2 added hole per lattice constant. We find a dimensional crossover fr…
The fundamental application of the ultrasonic pulse velocity method (UPV) in the study of concrete, consist in the analysis and estimation of the mechanical properties (compressive strength). The precission of the estimation may be dependent on the incidence of various factors, one of which is the water content acquir…
Oscillations of atomic nuclei in crystals are considered in this paper. It is shown that elastic nuclei oscillations relatively electron envelops (inherent, I-oscillations) and waves of such oscillations can exist in crystals at adiabatic condition. The types and energy quantums of I-oscillations for different atoms a…
The performance of chemical-vapor-deposited (CVD) diamond films as on-line dosimeters has been substantially improved after irradiation with fast neutrons up to a fluence of 5×1014 n/cm2. This is correlated to a decrease of more than one order of magnitude in the concentration of deep levels with activation energy in…
The optical functions of β-Ga2O3 thin films have been determined by ellipsometry from 0.74–5 eV. Several electron-beam evaporated and rf magnetron sputtered films of different thicknesses were investigated using a multisample technique. Refractive index values comparable to those of bulk material are found. Cauchy dis…
Electric, thermal, optical, and magnetic properties have been investigated for ferromagnetic (ferrimagnetic) ordered double perovskites, A2CrReO6 (A=Sr and Ca). Sr2CrReO6 is found to be a metallic ferromagnet with a high Curie temperature (TC=635 K), possibly the highest-TC half metal among the perovskite family. By c…
X-ray radiation is widely used in medical and industrial applications. The basic design of the x-ray tube has not changed significantly in the last century. In this paper, we demonstrate that medical diagnostic x-ray radiation can be generated using a carbon nanotube (CNT)-based field-emission cathode. The device can…
The heterogeneity of composite leads to the extra charge concentration at the boundaries of different phases that results essentially nonzero effective electric susceptability. The relation between tensors of effective electric susceptability $\hatχ_{ef}$ and effective conductivity $\hatσ_{ef}$ of the infinite two--di…
We present a fully three-dimensional study of the multiexciton optical response of vertically coupled GaN-based quantum dots via a direct-diagonalization approach. The proposed analysis is crucial in understanding the fundamental properties of few-particle/exciton interactions and, more important, may play an essentia…
We demonstrate efficient spin-polarized tunneling between a ferromagnetic metal and a ferromagnetic semiconductor with highly mismatched conductivities. This is indicated by a large tunneling magnetoresistance (up to 30%) at low temperatures in epitaxial magnetic tunnel junctions composed of a ferromagnetic metal (MnA…
A novel class of photosensitive organometallic precursor materials is used to pattern thin film mixed-metal oxide structures. In this work a photosensitive organometallic precursor is coated onto a silicon substrate and exposed to ultraviolet light through a mask to form patterned oxide structures. This is a negative-…
Substitution rules defined on the binary alphabet and invariant under the interchange of both participating symbols are considered. Typically, the resulting symbolic sequences are weakly disordered, and their Fourier spectra are singular continuous. Exact relations are derived which express the correlation dimension o…
Irreversible cis-to-trans photoisomerization behavior was observed for a stilbazole–porphyrin (1), and its zinc complex (2). trans-1 and trans-2 did not isomerize to the corresponding cis-isomer under irradiation with UV light, although stilbazoles readily undergo the trans-to-cis isomerization upon UV irradiation. In…
In this work molecular contamination of optical components such as e.g. reflective mirrors for extreme ultraviolet (EUV) lithography was experimentally studied using irradiation with keV electrons. Since secondary electrons are known to initiate most of the surface chemistry, radiation with EUV photons or electrons of…
Mesopores become micropores under pressure (10–50 MPa), which is applied to dahlia-shaped arrays of single-wall carbon nanohorns (SWNHs, see Figure for a TEM image) in liquid media, such as ethanol or glycerol. While the morphology of the arrays does not substantially change, the apparent volume shrinks by a factor of…