Impedance spectroscopy is a method of modeling materials with equivalent circuits to determine electrical properties, such as the resistivity and the dielectric constant. We explore impedance spectroscopy, both theoretically and experimentally through applying the method to samples of BaCuS1-xSexF. Grain boundary effects were dominant in the results, and although they...
We consider development of sand ripples in shallow water flows which do not reach an equilibrium height but have a time-varying ripple height that slowly reaches a maximum value and then is quickly destroyed by the fluid. A simple scenario to explain the time periodic behavior of the sand ripples...
When a nucleus is in an excited state, it will decay to lower energy by emitting photons. Often there are several intermediate stages in a decay cascade. Occasionally the photons in a cascade will be emitted in coincidence. This will be resolved by the detector not as two distinct photons,...
We report ²⁷Al and ⁶⁹,⁷¹Ga impurity and ⁶⁷Zn host species NMR experiments on
ZnO powders containing Al or Ga dopants in the range 0.03 to 3 at. %. Spectral
analysis of the ⁶⁷Zn and ⁶⁹Ga quadrupole powder patterns indicate gallium is
substitutional for zinc and the electric quadrupole coupling of...
Immersion energies for an impurity in a homogeneous electron gas with a uniform positive background charge density have been calculated numerically using density functional theory. The numerical aspects of this problem are very demanding and have not been properly discussed in previous work. The numerical problems are related to approximations...
We exhibit long-lived resonances in scattering from two-dimensional soft cage potentials comprised of three and four Gaussian peaks. Specific low-energy resonances with very narrow width are shown to correspond to classical multiple-reflection events. These states have much larger probability densities inside the cage than outside and mimic bound states in...
Angular correlations of gamma rays from excited states of ¹⁶⁶Er have been
measured following the β decays of ¹⁶⁶ Ho (Jπ =7-, t 1/2 =1200y, Q= 1854 ke V) and ¹⁶⁶Tm (Jπ = 2+, t 1/2, = 7.7h, Q=3040 keV).
Data was collected using the 8π
spectrometer, an array of...
As part of a research program to study the transitional region of N=88
isotones, ¹⁵²Tb was produced by the reaction ¹⁵¹Eu(α,3n)¹⁵²Tb in the 88" cyclotron
located at LBNL. Gamma-ray spectroscopy of the radiation emitted from excited
¹⁵²Gd following the β⁺ decay of ¹⁵²Tb has been performed using an array of...
Bulk properties of CuSc₁₋ₓMgₓO₂, CuSc₁₋ₓMgₓO₂₊y, BaCu₂S₂, Bai₁₋ₓKCu₂S₂, BaCu₂Se₂
and Bai₁₋ₓKₓCu₂Se₂ are investigated supporting the search for highly conductive p-type
thin films. Mg is an efficient dopant in CuScO₂ with conductivity up to l.5.10⁻² S/cm.
Oxidation of CuScO₂:Mg leads to further increase in conductivity up to 0.5 S/cm. The
amount of...
Zinc tin oxide (ZTO) films deposited by pulsed laser deposition (PLD) are
investigated as a channel layers for transparent thin-film transistors (TTFTs).
Films are deposited on glass for characterization, and transistor channel layers are
deposited onto aluminum oxide-titanium oxide/tin doped indium oxide/glass
substrates (ATO/ITO/glass) to produce TTFTs.
UV-visible spectroscopy on...
The Seebeck coefficient is examined in the high temperature limit, using an approach based on a grand partition function containing Hubbard Hamiltonian interaction terms. Although the carriers of interest occupy localized Wannier states, this work is prefaced by the case of delocalized Bloch states, which is examined using Boltzmann transport,...
Crystals of CdF₂:In and CdF₂:Ga reduced in a cadmium vapor exhibit unusual
metastable properties that can be explained by a "negative U" model. This work
uses NMR to investigate this model for CdF₂:Ga and CdF₂:Ga,Y and compare the
results to optical measurements. Temperature dependent relaxation measurements
were done on ¹¹³Cd...