Materials Literature
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Many crystalline solids fail by cleavage at low temperatures and by plastic processes at high temperatures. In the transition region, cleavage failure occurs at stresses increasing with increasing temperature, reflecting a decrease in yield stress and a consequent increase of plasticity around the crack tip. Crack tip…
Using a wide-field Kerr microscope, we have studied the magnetic domain structures of epitaxial and polycrystalline La0.67Sr0.33MnO3 thin films as well as a film having thermally induced 〈110〉 microcracks. The epitaxial film on a (001) SrTiO3 substrate has different magnetic domain behaviors for in-plane fields applie…
When molecules are subjected to static or dynamic uniform electric fields the effects are conveniently described in terms of dipole polarizabilities and hyperpolarizabilities. The fields act on both the electronic and vibrational motions simultaneously and, through perturbation theory, this leads to the exact sum-over…
We have investigated the structural and compositional changes that are induced by the segregation of substrate Mg to the surface of $1\ensuremath{\mu}$m-thick ${\mathrm{Fe}}_{3}$O${}_{4}(001)$ films on MgO(001). The thin films have been grown with plasma-assisted MBE. Characterization with reflection high-energy elect…
Photoluminescence (PL) and light absorption of Er-doped amorphous hydrogenated silicon are studied in the temperature range 77--300 K. In the linear pumping regime the intensity of the Er-induced luminescence decreases by a factor of about 15 in this temperature range. Frequency resolved spectroscopy shows that in the…
The electroluminescence (EL) from Si+ implanted SiO2 thin film prepared by thermal oxidation was compared with photoluminescence (PL) properties. Both EL and PL spectra indicate that the luminescence originate from the same three luminescence bands around 470, 600, and 730 nm. Annealing at temperatures below and above…
A Strategy for Structural-Acoustic Problems. Basic Notions on Variational Formulations. Linearized Vibrations of Conservative Structures and Structural Modes. Dissipative Constitutive Equation for the Master Structure. Master Structure Frequency Response Function. Calculation of the Master Structure Frequency Response…
We compare the thermal variations of ESR, dc, and microwave resistivity of unoriented bulk single wall carbon nanotube samples. We conclude that the ``metallic'' high-$T$ behavior $(d\ensuremath{\rho}/dT>$ 0) is an intrinsic property of the bulk material, and that the system remains metallic even at low temperature…
The electronic structure of the monoclinic phase of titanium monoxide and a vacancy-free rock-salt phase have been investigated using x-ray photoelectron spectroscopy and x-ray emission spectroscopy techniques. For the investigation of the monoclinic structure type, polycrystalline samples of titanium monoxide were us…
Transport and magnetic properties of ${R}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{TiO}}_{3+y/2}$ have been systematically investigated varying the one-electron bandwidth $(W)$ and the band filling $(n=1\ensuremath{-}\ensuremath{\delta}),$ which can be controlled by the $R$-dependent lattice distortion and by the C…
Quasi-hydrostatic-pressure measurements of electrical resistivity up to 11 kbar are presented for a series of manganese perovskites ${L}_{2/3}{A}_{1/3}{\mathrm{MnO}}_{3}.$ It is found that the Curie temperature ${T}_{C},$ being itself a function of the electronic bandwidth $W,$ displays a larger variation of $d\mathrm…
Using a combination of photoelectron and inverse photoelectron spectroscopy, we show that the band gap in a monolayer of C 60 on a Ag surface is strongly reduced from the solid C 60 surface value. We argue that this is a result of the reduction of the on-site molecular Coulomb interaction due to the influence of image…
In this paper we apply nonlocal kinetic coupling to the dynamic mean-field density functional method, which is derived from generalized time-dependent Ginzburg–Landau theory. The method is applied to the mesoscopic dynamics of copolymer melts, which was previously simulated using a local coupling approximation. We dis…
The properties of vacancy aggregates in crystalline silicon are studied using density-functional-based molecular-dynamics simulations in large periodic supercells as well as approximate ab initio and ab initio Hartree Fock in molecular clusters. The stability and properties of aggregates of up to seven vacancies are d…
The metal-insulator $(M$-$I)$ phase transitions relevant to charge ordering (CO) have been investigated for perovskite-type ${(\mathrm{N}\mathrm{d}}_{1\ensuremath{-}y}{\mathrm{Sm}}_{y}{)}_{1/2}{\mathrm{Sr}}_{1/2}{\mathrm{MnO}}_{3}$ $(0<~y<~1)$ crystals, in which the one-electron bandwidth $(W)$ is systematically…
Successful observation of persistent spectral hole burning in CdTe quantum dots embedded in the glass enabled us to investigate their size-dependent electronic energy levels. Luminescence excitation spectroscopy was utilized to confirm them. The observed size-dependent electronic transitions show a monotonic increase…
We have investigated the ferroelectric polarization of the perovskite oxide ${\mathrm{KNbO}}_{3}$ within the self-consistent Hartree-Fock (HF) method, where the crystalline orbitals are expanded over a set of localized functions. According to the modern theory, macroscopic polarization is a geometric quantum phase: he…
We have studied the growth of ultrathin Au films on the ${\mathrm{TiO}}_{2}$ (110) surface using low-energy ion scattering (LEIS), x-ray photoelectron spectroscopy (XPS), and low-energy electron diffraction (LEED). For substrate temperatures of 160 and 300 K, for fractional monolayer Au coverages, Au evaporated under…
We present an analysis of the stability of a dendrite against a small perturbation to the tip velocity. We find that dendritic growth in pure metals and alloys will become unstable above some upper critical undercooling ΔT2*. In alloys above a critical concentration, dendritic growth may also become unstable below a l…
A systematic transport study of the ballistic electron emission microscopy (BEEM) of Au/Si(100) and Au/Si(111) Schottky barriers for different thicknesses of the metal layer and different temperatures is presented. It is shown that the existing experimental data are compatible with a recently predicted bandstructure-i…