Materials Literature
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Cr 3+ and Fe 3+ ions are used as paramagnetic probes of the local order in diamagnetic transition metal fluoride glasses (TMFG). EPR observations are made at S, X, K and Q band frequencies at different temperatures. It follows from the frequency dependence of the spectra that Cr 3+ and Fe 3+ ions are characterized by…
Induced optical absorption in three SiO2-core/SiO2:F-clad fibers (two high-OH, one low-OH) and one SiO2:Ge-core fiber was investigated in situ in the range 415–1100 nm during repeated 60Co γ-ray exposures to doses ≳1 MGy(Si). Injected visible light (∼5 μW) was maintained during the first and second irradiations at ∼27…
Growth and structural evolution of a MgO thin film fabricated on Si substrate by using sol-gel method were investigated. Textured MgO films displaying (111) MgO∥(100)Si and (111)MgO∥(111)Si orientations were obtained. Crystallization of (111) oriented MgO film was observed to occur above 500 °C regardless of the subst…
Rocking curves of reflection high-energy electron diffraction (RHEED) have been measured from the Si(111)-(\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 )R30\ifmmode^\circ\else\textdegree\fi{}-Al, -Ga, and -In surfaces at [21\ifmmode\bar\else\textasciimacron\fi{} 1\ifmmode\bar\else\textasc…
Using a first-principles technique, we calculate the structural, electronic, and vibrational properties of the (100), (111), and (110) surfaces of diamond. Stable (2\ifmmode\times\else\texttimes\fi{}1) and Pandey chain reconstruction were found for the bare (100) and (111) surfaces, respectively. The surface zigzag ch…
The thermoelectric properties of systems in the form of superlattices have been studied. First, the electrical and thermal conductivities, the thermopowers, and the figures of merit of superlattice structures are given in terms of the bulk parameters of the two constituent materials for conduction both parallel and pe…
Submicroporous CdS films were fabricated by a two-step replication process, in which porous anodic alumina was used as a template. The films were grown on a porous gold support of the same structure, resulting in a free-standing CdS/Au membrane. The diameter of the holes of the regular porous structure is in the order…
A statistically based characterization of the topography of a multidimensional potential surface classifies not only local minima and saddles but entire basins containing many minima, and divides separating basins and monotonic sequences of local minima within each basin. The data fold readily into the formalisms of c…
Diffusion of boron, lithium, nitrogen, oxygen, and hydrogen into type IIa natural diamond was studied. The diffusion was performed in two steps. First, diffusion of Li and oxygen was performed in nitrogen atmosphere at 860 °C for one hour. The sample was then placed in a hot filament chemical vapor deposition (CVD) gr…
Frequency-dependent self-diffusion coefficients ${D}_{s}(\ensuremath{\omega})$ for both particle species of a supercooled binary hard-sphere liquid have been calculated within a mode-coupling approximation. For a disparate-size mixture we find a glass transition at a critical packing fraction ${\ensuremath{\eta}}_{B}$…
The molecular adsorption of nitrogen on nickel clusters is used to probe the clusters’ geometrical structures. The application of nitrogen binding rules derived from earlier studies of both larger and smaller nickel clusters allows a determination of structure from nitrogen uptake patterns. In the 16- and 28-atom size…
The present work employs the total-energy pseudopotential technique within the local density approximation to determine the electronic structure and the full set of elastic constants of cubic BN which have not been directly established experimentally. We obtain ${\mathit{C}}_{11}$=8.44, ${\mathit{C}}_{12}$=1.9, and ${…
We describe a general and efficient method, based on computer simulations and applicable to a general class of fluids, that allows us to determine (i) bounds on the transition densities of the melting transition that are valid in the thermodynamic limit and (ii) the order of the phase transition. The bond-orientationa…
The electrical conductivity, the thermoelectric power, and the electrical contribution to the thermal conductivity of superlattices have been studied within the envelope-function approach for the electrons. The effects of tunneling through the barriers due to finite potential offsets and of the thermal currents throug…
Highly (100)-oriented LaNiO3(LNO) thin films were grown on Si, SiO2/Si, Pt/SiSiO2/Si, as well as glass substrates by rf magnetron sputtering deposition at substrate temperatures ranging from 150 to 500 °C. As-deposited LNO films are metallic; those prepared at substrate temperature ∼150–250 °C have a resistivity of 0.…
Carbon nitride (CNx) films were prepared by reactive pulsed laser deposition at nitrogen partial pressure PN2varying from 0 to 300 mTorr. It is found that the atomic fraction of nitrogen f in the films first increases with increasing PN2, reaches a maximum of 0.32 at PN2=100 mTorr, and then decreases to a saturated va…
The metal-insulator transition of La 3 Ni 2 O 7-δ with 2-dimensional electrons has been studied. Various physical properties can be understood by introducing a model of charge orderings in the NiO 2 planes induced by oxygen orderings. Arguments on the non-occurrence of the superconductivity are also given.
A complete mapping in the Brillouin zone of the structural instability associated with the ferroelectric phase transitions of ${\mathrm{KNbO}}_{3}$ has been obtained by first-principles calculations using a linear response approach. The wave-vector dependence of the instability reveals pronounced two-dimensional chara…
The oxidation of sputtering deposited copper thin films has been investigated. Phase identification and surface morphology characterization were performed by x-ray diffraction, Raman spectroscopy, and atomic force microscopy (AFM). The copper film is first oxidized to Cu2O below 300 °C and then to CuO at higher temper…
Experimental and theoretical graphite valence-band photoelectron angular distributions are presented and compared. We observe a zone-selection effect, wherein interference between photoelectron amplitudes from the two atoms in each graphene unit cell cause both \ensuremath{\sigma} and \ensuremath{\pi} states to appear…