Shear-induced critical dynamics in a nonionic micellar solution has been investigated by measuring the viscosity η as a function of the shear rate S and a characteristic crossover temperature associated with S. The viscosity very close to ${\mathit{T}}_{\mathit{c}}$ varies as ${\mathit{S}}^{\mathrm{-}\mathrm{\omega }}$ with ω=0.021±0.003 in excellent agreement with the expected value of ω=0.021. We also find a simple scaling relation between the temperature dependence and shear-rate dependence of η. In addition, we confirm the feasibility of observing phase-separation dynamics near the critical point by shear quenching.

The structure factor of the lyotropic liquid-crystal cesium perflouro-octanoate–water after the material has been quenched form the isotropic phase to the nematic phase was found to display non-Porod power-law behavior in the limit of large wave vectors. Our measurements were consistent with the scaling law S(q,t)∼${\mathit{t}}^{\mathrm{-}3/2}$${\mathit{q}}^{\mathrm{-}6}$ for bulk samples and S(q,t)∼${\mathit{t}}^{\mathrm{-}1}$${\mathit{q}}^{\mathrm{-}4}$ for thin samples exhibiting two-dimensional behavior. Dimensional crossover was also observed.

We have performed wide-time-range photon correlation spectroscopy (PCS) on poly(propylene glycol) to probe the dynamics in the glass transition range. In addition to the primary (α) relaxation which shows stretched-exponential behavior, we observe two relaxation processes not witnessed in PCS before. They are assigned to α’ and β processes and exhibit similar power-law decays. All three relaxations are analyzed in terms of recent mode-coupling theories and the inherent scaling relations are verified by independent determinations of the relevant exponents from the spectra.

Wetting of antiphase boundaries (APB) close to the order-disorder transition ${\mathit{T}}_{\mathit{c}}$ is studied in the alloy Cu-Pd (17%) using dark-field transmission electron microscopy. Highly controlled heat treatments every 0.2 °C just below ${\mathit{T}}_{\mathit{c}}$ are performed and about 100 APB per temperature are examined. The observed temperature dependence of the APB is logarithmic. Because of the existence of a small two-phase region, a crossover between a wetting regime and a two-phase regime is expected, but a we show that in the logarithmic law remains valid up to less than 0.2 °C below the lower critical temperature. From the logarithmic fit of the width the correlation length is found to be equal to 1.3 nm.

Water adsorption on polished (111) surfaces of ${\mathrm{BaF}}_2$ and ${\mathrm{CaF}}_2$ was studied at room temperature under ultrahigh vacuum conditions by optical second-harmonic generation. Above ${10}^4$ langmuirs, the total second-harmonic yield decreases with increasing exposure. The azimuthal anisotropy is influenced differently on each substrate. Below ${10}^4$ langmuirs the 3m symmetry of the crystal surface is preserved in both cases, but more pronounced for ${\mathrm{CaF}}_2$. At high doses the symmetry remains for ${\mathrm{BaF}}_2$, but vanishes for ${\mathrm{CaF}}_2$. The results point to pseudomorphous epitaxial growth of water on ${\mathrm{BaF}}_2$ but not on ${\mathrm{CaF}}_2$.

Atomic force microscopy reveals straight slip steps resulting from dislocation glide in the primary {100}〈110〉 glide system in ‘‘low mismatch’’ ${\mathrm{CaF}}_2$/Si(111) structures. From the height and spacing of the steps, the strain relieved by these misfit dislocations is compatible with the relief of the tensile thermal strain change on cooldown. In ‘‘high mismatch’’ ${\mathrm{BaF}}_2$/${\mathrm{CaF}}_2$/Si(111) structures, dislocations which relieve the thermal mismatch change are mobile, while the 14% lattice mismatch is mainly overcome by sessile misfit dislocations with Burgers vectors parallel to the interface.

A new method is introduced to calculate response functions within Density Functional Theory. It uses a conjugate-gradient algorithm applied to a variational expression from perturbation theory. The dielectric tensor, Born effective charges, and TO and LO phonons at q=0 are obtained. A one-parameter scissors operator gives the dielectric tensor within 0.5% of the experimental value. The anisotropy of the effective charge tensor is shown to be crucial for reproducing the LO-TO splittings.

The second-order correction to the free energy due to the interaction between electrons is calculated for a quasi-one-dimensional conductor exposed to a magnetic field perpendicular to the chains. It is found that specific heat, magnetization and torque oscillate when the magnetic field is rotated in the plane perpendicular to the chains or when the magnitude of magnetic field is changed. This new mechanism of thermodynamic magnetic oscillations in metals, which is not related to the presence of any closed electron orbits, is applied to explain behavior of the organic conductor (TMTSF${)}_2$${\mathrm{CLO}}_4$.

The band dispersion of the localized, F 2p-like valence band of LiF is mapped using an imaging technique to obtain k(E). The bandwidth is 3.5 eV (from ${\mathrm{\Gamma }}_{15}$ to ${\mathrm{X}}_4^{\prime }$). This is 17% wider than predicted by first-principles band calculations, implying an expansion of the bandwidth by self-energy effects in qualitative agreement with quasiparticle calculations. The self-energy effect is opposite to that seen in delocalized systems, such as alkali metals.

The critical behavior of sliding charge-density waves just above threshold is analyzed. In 4-ε dimensions, the exponent ζ, defined through ${\mathit{I}}_{\mathrm{CDW}}$∼(V-${\mathit{V}}_{\mathit{T}}$${)}^{\mathrm{\zeta }}$, is found to be 1-ε/6+O(${\mathrm{\epsilon }}^2$). Two different correlation lengths are found, with exponents ν=1/2 exactly and ${\nu }_{\mathrm{FS}}$=2/d+O(${\mathrm{\epsilon }}^2$). These results compare favorable with recent numerical results in two and three dimensions.

We have discovered a DX center in InP:S under hydrostatic pressure greater than 82 kbars. This defect exhibits the persistent photoconductivity typical of such centers. The optical ionization energy for this new DX center is between 0.86 and 1.02 eV, and we have measured the energy dependence of the optical absorption cross section. The thermal barrier for capture from the shallow donor state into the deep DX state is in the range 0.23–0.33 eV. We estimate that at zero pressure the energy of the DX center lies 0.51±0.07 eV above the Γ conduction-band minimum.

Exchange enhancements of the spin-polarized 2D electron gas are determined for the first time by inelastic light scattering from spin-flip inter-Landau-level and intersubband excitations. In the magnetic quantum limit ν=1 the splitting between long wavelength magnetoplasmons and spin-flip inter-Landau-level excitations is a direct spectroscopic measurement of the enhanced exchange energy. At ν=1 the enhancements in GaAs quantum wells are in agreement with the Hartree-Fock approximation.

To study incommensurate spin systems, we employ a collective Monte Carlo trial that enables the system to choose its own boundary conditions. The method is tested on a generalization of the 2D fully frustrated triangular lattice of XY spins. Even for small sizes of our model system, the bulk value for the pitch is obtained. Convergence as a function of size is far better than can be obtained with free or periodic boundary conditions. Moreover, this approach yields the temperature dependence of the pitch in the modulated phase. The spiral-to-antiferromagnetic phase transition appears to be continuous and a Lifshitz point occurs at finite temperature.

It is rigorously proven that classical O(n) and quantum spin-s Heisenberg ferromagnetic models on generic networks cannot have spontaneous magnetization at any finite temperature if random walks on the same structure are recursive. It follows as a corollary that on fractals a continuous symmetry can be spontaneously broken only if the spectral dimension is greater than 2.

Dielectric relaxation profiles and self-diffusion coefficients were measured for 1,1,1-trichloroethane, t-butyl chloride, and 2,2-dinitropropane in liquid and plastic phases. For all threee samples no significant change in the relaxational behavior is observed when going from liquid to plastic-crystal phases. The comparison of the results with the extended hydrodynamic model shows that the model overestimates the effect of translational-rotational coupling on dielectric properties of liquids.

The Fermi-edge singularity in optical spectra is studied theoretically using the Tomonaga-Luttinger model for one-dimensional (1D) systems. Its critical exponent is obtained analytically for an arbitrary mass of a valence hole taking into account the electronic correlation. The exponent is found to be independent of the hole dynamics in 1D, which is in striking contrast to the 2D and 3D cases. Weak repulsive interaction among the conduction electrons sharpens the power-law peak in the edge spectrum.

Extraordinarily large circular dichroism has been observed in the near-edge x-ray absorption of the Fe 2${\mathit{p}}^{3/2}$ and 2${\mathit{p}}^{1/2}$ lines of monolayer magnetic films of Fe on Cu(001). This is the first reported observation of normal incidence dichroism in a metal overlayer. Analysis of such large variations using a simple and concise theoretical formulation suggests a saturation of the dichroism effect. This anlaytical approach also permits an approximate determination of the magnetic moment directly from experimental parameters.

We used diffusing wave spectroscopy to determine the phase diagrams of binary mixtures of charge-stabilized colloidal particles of different dimensions in the low-screening limit. As the ratio of radii r=${\mathit{r}}_1$/${\mathit{r}}_2$ was increased progressively towards 1, the structure of the diagrams evolved from eutecticlike to azeotropiclike and finally to a diagram where complete solubility was found, much like in atomic systems. We present for the first time evidence for liquid-galss transitions in these strongly interacting systems as the relative composition of both species is varied.

We have made the first direct observation of a new class of elastic interface waves that propagate along the discontinuity of a fracture in a solid. Two propagating eigenmodes were detected in a synthetic fracture in aluminum. The waves are dispersive and polarization dependent, verifying theoretical predictions. The existence of these waves has broad implications, requiring reinterpretation of data from seismic exploration, earthquake detection and nondestructive testing.

We study an origin of avoided crossings for classically nonintegrable systems. Using a diabatic transformation, we show that characteristic features of ‘‘scars’’ continuously change along diabatic lines. Moreover, through Fourier transformation of an energy level density, we suggest that avoided crossings in fully chaotic systems originate from the long periodic orbits winding around scars.