Materials Literature
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The low-temperature dc conductivity and magnetoconductivity of ion-implanted (${\mathrm{Ar}}^{+}$) and chemically doped (${\mathrm{H}}_{2}$${\mathrm{SO}}_{4}$) polyaniline films have been studied. The metal-insulator transition has been observed for ion-implanted polyaniline films on increasing the irradiation dose to…
We have analyzed the ab initio local-density-approximation band-structure calculations for the family of perovskite oxides, LaM${\mathrm{O}}_{3}$ with M=Ti--Ni within a parametrized nearest-neighbor tight-binding model, and extracted various interaction strengths. We study the systematics in these interaction paramete…
The interionic solution structures of trans -[Ru(PMe 3 ) 2 (CO)(COMe)(pz 2 -CH 2 )]BPh 4 and trans -[Ru(PMe 3 ) 2 (CO)(COMe)(η 2 -pz 3 -CH)]BPh 4 have been “directly” investigated by the detection of interionic contacts in 1 H-NOESY NMR spectra between the protons of the organometallic fragments and those of the count…
Photoabsorption spectra of isolated ${\mathrm{Ga}}_{\mathit{N}}$${\mathrm{As}}_{\mathit{M}}$ clusters (N+M=4--80) have been investigated in the range \ensuremath{\Elzxh}\ensuremath{\omega}=1.7--6.4 eV by measuring their absolute photodissociation and photoionization cross sections. The results are analyzed in terms of…
The absorption coefficient of CuGe${\mathrm{O}}_{3}$ was measured in the energy range of 1-4 eV, in a temperature interval between 300 and 20 K, for light polarized along the $b$ and $c$ crystal axes. A weak absorption band at 1.7 eV is attributed to copper $d\ensuremath{-}d$ transitions partially allowed by electron-…
The mean escape depth (MED) of the signal photoelectrons in x-ray photoelectron spectroscopy (XPS) is a useful measure of the surface sensitivity in XPS measurements. The MED has previously been given by the product of the inelastic mean free path for the signal electrons and the cosine of the photoelectron emission a…
An ac calorimetric method is applied to the direct measurement of thermal diffusivity of single fibers. Theoretical analysis is presented, taking into account the two-dimensional ac thermal wave for cylindrical systems and the effect of time delay at the temperature detecting system. Experimental tests are performed u…
The influence of magnetic ordering on the NiO valence band has been studied by angle resolved photoelectron spectroscopy. Measurements have been performed at temperatures above and below the N\'eel temperature (${\mathit{T}}_{\mathit{N}}$), as well as at room temperature. The results show temperature dependence but no…
Within the local-density approximation we have used the linear muffin-tin orbital method, without geometrical approximations, to calculate the electronic structure of red ${\mathrm{HgI}}_{2}$. Using the self-consistent potential we have calculated the energy bands and from these derived the anisotropic frequency-depen…
Thin layers of amorphous hydrogenated carbon (a-C:H) deposited on (100)Si/${\mathrm{SiO}}_{2}$ substrates were studied using atomic force microscopy, electron spin resonance (ESR), and internal photoemission spectroscopy. Layers with optical band gap in the range 3--0.7 eV were found to be homogeneous with respect to…
The Born effective charge ${\mathrm{Z}}^{\mathrm{*}}$ and dielectric tensor ${\mathrm{\ensuremath{\epsilon}}}_{\mathrm{\ensuremath{\infty}}}$ of ${\mathrm{KNbO}}_{3}$ are found to be very sensitive to the atomic geometry, changing by as much as 27% between the paraelectric cubic and ferroelectric tetragonal and rhombo…
In order to clarify the nature of the neutral Mn acceptor in GaP, we have carried out optical-absorption and electron-paramagnetic-resonance (EPR) experiments using both conventional and thermally detected EPR on semi-insulating GaP:Mn. In thermal equilibrium at low temperatures, all the manganese occurs in the charge…
Recent studies on proteins whose N and C termini are in close proximity have demonstrated that folding of polypeptide chains and assembly of oligomers can be accomplished with circularly permuted chains. As yet no methodical study has been conducted to determine how extensively new termini can be introduced and where…
The large single crystals of stoichiometric and nonstoichiometric Gd monopnictides GdX (X=P, As, Sb, and Bi) are grown by the mineralization method (for X=P and As) and Bridgman method (for X=Sb and Bi). A systematic investigation of the transport properties of GdX single crystals is presented. We report on measuremen…
We prepared nonresonant-type homogeneous glasses containing Bi(2)O(3) by the melting method. The thirdorder optical nonlinear susceptibility chi((3)) was found by third-order harmonic generation measurement to be 9.3 x 10(-12) esu. We attribute the nonlinearity of these glasses to the large molar refraction of glasses…
We present a structural and vibrational analysis of several amorphous (disordered) and ordered isomers of a 55-atom gold cluster. A Gupta n-body potential, with parameters fitted to gold clusters, was used to model the metallic bonding in the ${\mathrm{Au}}_{55}$ cluster. The molecular-dynamics method combined with si…
Insulator-metal transitions and related electronic structures have been investigated for single crystals of perovskite-type cobalt oxides $R\mathrm{Co}{\mathrm{O}}_{3}(R=\mathrm{L}\mathrm{a},\phantom{\rule{0ex}{0ex}}\mathrm{P}\mathrm{r},\phantom{\rule{0ex}{0ex}}\mathrm{N}\mathrm{d},\phantom{\rule{0ex}{0ex}}\mathrm{S}\…
A study of the thermoelectric properties of the skutterudite compound CoSb3 was carried out on single crystals grown by the Bridgman gradient freeze technique. p- and n-type samples were obtained over a wide range of carrier concentration. Undoped As-grown crystals show p-type conductivity while n-type samples were ob…
Conventional continuum damage descriptions of material degeneration suffer from loss of well-posedness beyond a certain level of accumulated damage. As a consequence, numerical solutions are obtained which are unacceptable from a physical point of view. The introduction of higher-order deformation gradients in the con…
We report on low-temperature (77 K) far infrared attenuated total reflection (ATR) spectroscopic measurements on a short period GaAs/AlAs superlattice, and discuss the optics of the modes observed. We assess the significance of the ATR technique for determining superlattice phonon parameters. We model the results usin…