Materials Literature
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In this paper we present and discuss experimental results on molecular mobility in propylene glycol and its three oligomers confined to the ∼100 Å pores of a controlled porous glass. The objective is to elucidate the finite size effects on the dynamics of hydrogen-bonded liquids of different molecular weights but iden…
We study the dynamics of adatoms in a model of vicinal (11m) fcc metal surfaces. We examine the role of different diffusion mechanisms and their implications to surface growth. In particular, we study the effect of steps and kinks on adatom dynamics. We show that the existence of kinks is crucially important for adato…
Elastic matrix distortion around a growing inclusion of a new phase is analyzed and the associated contribution to the Gibbs free energy is considered. The constant-composition transformation from the parent to product phase is considered within the frame of Landau theory of phase transitions. The volume misfit betwee…
A theoretical analysis is presented for the morphological evolution and stability of transgranular wedge-shaped voids in conductor lines with bamboo grain structure under an applied electric field. A linear stability analysis identifies void shapes that become unstable with respect to the growth of perturbations with…
The paramagnetic radicals formed in the TL phosphors BaSO 4 :Eu and BaSO 4 :Eu, P have been studied using the technique of ESR. Two radicals assigned to SO 2 - , were observed at room temperature. One of them exhibits a hyperfine interaction with a nearby cation. Step annealing measurements suggest a connection betwee…
The coherency of the domain walls forming between the a and c domains in epitaxial lead titanate films forces a tilt in the a-domains with respect to the surface normal of the (001)SrTiO3 substrate. It is shown that the measurement of the relative volume fraction of the domains requires mapping of the x-ray diffractio…
We propose a microscopic model without energy barriers in order to explain some generic features observed in structural glasses. The statics can be exactly solved while the dynamics has been clarified using Monte Carlo calculations. Although the model has no thermodynamic transition, it captures some of the essential…
Voltage offsets in the polarization-voltage characteristics of Pb(Zr,Ti)O3 capacitors can be induced by either thermal or optical processes. The thermally (optically) induced voltage shift occurs by heating (illuminating) the sample under remanence or a saturating bias. Generally speaking, the thermally induced voltag…
Two-particle calculations, which include the electron-hole Coulomb interaction nonperturbatively, are performed for excitons in surface passivated Si nanocrystals. The calculated exciton energies agree quantitatively with photoluminescence data. The exciton charge distributions differ markedly from those obtained in s…
The magnetism of an insulator, $\ensuremath{\kappa}$-(BEDT-TTF${)}_{2}$Cu[N(CN${)}_{2}$]Cl, situated near the 10 K superconducting phase in $\ensuremath{\kappa}$-type BEDT-TTF family, has been studied by ${}^{1}$H NMR for the first time. A commensurate antiferromagnetic ordering with a moment of (0.4--1.0) ${\ensurema…
It is shown that the local spin-density approximation describes well electronic structures of perovskite $\mathrm{La}M{\mathrm{O}}_{3}$ ( $M\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}$ Mn, Fe, Co, Ni) for the ground-state and single-electron excited-state properties. Inclusion of details of crystal structures…
We present a general scheme for the computation of the time dependent (TD) quadratic susceptibility ($χ^{(2)}$) of an extended insulator obtained by applying the `$2n+1$' theorem to the action functional as defined in TD density functional theory. The resulting expression for $χ^{(2)}$ includes self-consistent local-f…
Cubic structured CdS, CdSe, and CdTe, II–VI semiconductor nanoparticles have been synthesized using aqueous solution precipitation at room temperature. The ‘‘as-prepared’’ particles have a size of about 30 Å. Thermal annealing causes (a) an increase in particle size; (b) a structural transition from the cubic to the b…
We present results of temperature and magnetic field dependent resistivity ρ(H,T) and bulk magnetization M(H,T) measurements on post-annealed La0.7Ca0.3MnO3 thin films that were grown via pulsed-laser deposition. Both the resistivity and the anomalously large negative magnetoresistance peak near the ferromagnetic orde…
We propose a heterogeneous reaction-diffusion model for the hydration and setting of cement. The model is based on diffusional ion transport and on cement specific chemical dissolution/precipitation reactions under spatial heterogeneous solid/liquid conditions. We simulate the spatial and temporal evolution of precipi…
An extension of the evolution strategy for mixed-integer optimizationproblems is introduced. The resulting generalized evolution strategy is applied to the problem of optical multilayer coating design and the results are compared with results obtained by standard methods. The generalized evolution strategy as a synthe…
This paper explains the origin of the ferroelectric instability in LiNbO3 and LiTaO3 and compares the electronic structures and energetics of the two materials.
Resonant tunneling through semimetallic ErAs quantum wells embedded in GaAs structures with AlAs barriers was recently found to exhibit an intriguing behavior in magnetic fields which is explained in terms of tunneling selection rules and the spin-polarized band structure including spin-orbit coupling.
The band structures of 6H and 4H SiC calculated by means of the FP-LMTO method are used to determine the effective mass tensors for their conduction-band minima. The results are shown to be consistent with recent optically detected cyclotron resonance measurements and predict an unusual band filling dependence for 6H-…
A new method to obtain a local parameterization for the exchange term in the many--body electronic problem is presented. The approach amounts to the introduction of a coordinate dependent electron effective mass. Numerical results for metallic clusters in the jellium model are compared with other standard methods.