Materials Literature
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We report results on the direct observation of the microscopic origins of backswitching in ferroelectric thin films. The piezoelectric response generated in the film by a biased atomic force microscope tip was used to obtain static and dynamic piezoelectric images of individual grains in a polycrystalline material. We…
We report on dielectric susceptibility measurements for the glass-forming systems toluene and 1-propanol, both of which exhibit slow secondary relaxation (Johari β-process). We present a complete lineshape analysis for both α- and β-process covering the real and imaginary parts. The observation of secondary relaxation…
The nonrelativistic energy loss suffered by fast electrons passing near dielectric interfaces of arbitrary shape is calculated by solving Poisson's equation using the boundary-charge method. The potential induced by a moving electron is expressed in terms of surface-charge distributions placed at the interfaces. These…
We report an ab initio evaluation of the surface energy of a simple metal, performed via a coupling-constant integration over the dynamical density-response function. The rapid rate of change of the electron density at the surface is treated exactly. Long-range correlations are treated self-consistently in the random-…
We describe quantitative imaging of the sheet resistance of metallic thin films by monitoring frequency shift and quality factor in a resonant scanning near-field microwave microscope. This technique allows fast acquisition of images at approximately 10 ms per pixel over a frequency range from 0.1 to 50 GHz. In its cu…
The homoepitaxial growth of initially flat surfaces has so far always led to surfaces which become rougher and rougher as the number of layers increases: even in systems exhibiting ``layer by layer'' growth the registry of the layers is gradually lost. We propose that pulsed glancing-angle sputtering, once per monolay…
In practical implementations of density-functional theory, the only term where an orbital description is needed is the kinetic one. Even this term in principle depends on the density only, but its explicit form is unknown. We provide a novel solution of the N-representability problem for an extended system, which impl…
We present a new method to measure attractive interactions between colloidal particles, and determine the nature of the attraction between particles suspended in a nematic liquid crystal. We confine droplets filled with ferrofluid to a thin layer and apply a magnetic field to induce dipole moments that drive the dropl…
Dissipative particle dynamics (DPD) does not conserve energy and this precludes its use in the study of thermal processes in complex fluids. We present here a generalization of DPD that incorporates an internal energy and a temperature variable for each particle. The dissipation induced by the dissipative forces betwe…
Crystallographic data, electrical and thermal transport measurements, and magnetic susceptibility values are reported for several compounds and alloys with the filled skutterudite structure, ${R}_{1\ensuremath{-}y}{\mathrm{Fe}}_{4\ensuremath{-}x}{\mathrm{Co}}_{x}{\mathrm{Sb}}_{12}$ ($R=\mathrm{La},$ Ce, or Th; $0<y…
I consider several N-body problems for which exact (bosonic) ground state and a class of excited states are known in case the N-bodies are also interacting via harmonic oscillator potential. I show that for all these problems the exact (bosonic) ground state and a class of excited states can also be obtained in case t…
We describe near-field imaging of sample sheet resistance via frequency shifts in a resonant coaxial scanning microwave microscope. The frequency shifts are related to local sample properties, such as surface resistance and dielectric constant. We use a feedback circuit to track a given resonant frequency, allowing me…
A smectic liquid-crystal phase made from achiral molecules with bent cores was found to have fluid layers that exhibit two spontaneous symmetry-breaking instabilities: polar molecular orientational ordering about the layer normal and molecular tilt. These instabilities combine to form a chiral layer structure with a h…
Various theoretical methods for calculating diffraction profiles of perfect crystals are available in literature. Although these methods hold within certain validity ranges due to their inherent approximations, they constitute the current state-of-the-art of numerical computation of diffraction profiles. In this paper…
By means of a variational approach we study the conditions under which a polyelectrolyte in a bad solvent will undergo a transition from a rod-like structure to a ``necklace'' structure in which the chain collapses into a series of globules joined by stretched chain segments.
We propose a new method to investigate interactions involved in atomic force microscopy (AFM). It is a dynamical method relying on the growth of oscillations via parametric resonance. With this method the second and third derivatives of the tip-surface interaction potential can be measured simultaneously. Because of i…
Trace maps for products of transfer matrices prove to be an important tool in the investigation of electronic spectra and wave functions of one-dimensional quasiperiodic systems. These systems belong to a general class of substitution sequences. In this work we review the various stages of development in constructing…
Spectrum of excitons in double-quantum-well structures is calculated in tilted magnetic field. It is shown that spectrum becomes asymmetric in quasimomentum if a transverse in respect to growth direction component of magnetic field is nonzero. A transition from $k$-space direct exciton ground state to $k$-space indire…
This Letter reports an experimental study of the dynamics of granular materials when vibrated horizontally. Convective motion is observed over wide range of parameters, similarly to the known effect observed under vertical vibration. However, under horizontal vibration we observe a striking novel effect on the oscilla…
Residual structure in the denatured state of a protein may contain clues about the early events in folding. We have simulated by molecular dynamics the denatured state of barnase, which has been studied by NMR spectroscopy. An ensemble of 10(4) structures was generated after 2 ns of unfolding and following for a furth…