Interface broadening during ion plating

Radiation damaged fluorite single crystals iso-thermally annealed showed an oscillating structure of the intensity of a diffracted neutron beam. This is in accord with previous report on crystalline cobaltic compound examined for reconstitution of parent complex ions from recoil hot atoms and for annealing of radiation damage by neutron diffraction. The oscillation phenomenon already found by radiochemical means in various solids irrespectively of their chemical constitution combined by a pure physical method as the neutron diffraction, greatly supports a hypothesis of a spatial temporal oscillatory diffusion of defects in isothermal annealing of radiation damaged crystalline lattice.     

Entanglement and decoherence of a micromechanical resonator via coupling to a Cooper-pair box

We analyze the quantum dynamics of a micromechanical resonator capacitively coupled to a Cooper-pair box. With appropriate quantum state control of the Cooper box, the resonator can be driven into a superposition of spatially separated states. The Cooper box can also be used to probe the decay of the resonator superposition state due to environmental decoherence.     

The Four-Body System Made up of Hydrogen and Antihydrogen

 In view of current interest in the trapping of antihydrogen atoms at low temperatures [1–3], we have investigated the reasons for considering that does not have a bound state. We go on to carry out a four-body variational calculation for s-wave hydrogen-antihydrogen scattering, using the Kohn variational method. This is a continuation of earlier work on interactions [5–7]. Received October 30, 2001; accepted for publication November 21, 2001     

Quadrupole corrections to matrix elements of transitions in resonant reactions of muonic molecule formation

The calculated resonant formation rates of the muonic molecules ddµ and dtµ are presented. The approach developed earlier for calculating the transition matrix elements in the dipole approximation has been extended to include the quadrupole terms in the multipole expansion of the interaction operator. The calculated dependence of the dtµ formation rates on the energies of the incident tµ muonic atoms shows that the effect of including the quadrupole correction is to reduce the magnitude of the peak rates by about 20–30% at the different temperatures, compared to those calculated in the dipole approximation. The dependence on temperature for the ddµ formation rates is obtained with the differences between the presented and previous calculations being less than 5%.     

Spin-1/2 Maxwell Fields

Requiring covariance of Maxwell's equations without a priori imposing charge invariance allows for both spin-1 and spin-1/2 transformations of the complete Maxwell field and current. The spin-1/2 case yields new transformation rules, with new invariants, for all traditional Maxwell field and source quantities. The accompanying spin-1/2 representations of the Lorentz group employ the Minkowski metric, and consequently the primary spin-1/2 Maxwell invariants are also spin-1 invariants; for example, ²–A ², E ²–B ²+2i EB–(₀ +A)². The associated Maxwell Lagrangian density is also the same for both spin-1 and spin-1/2 fields. However, in the spin-1/2 case, standard field and source quantities are complex and both charge and gauge invariance are lost. Requiring the potentials to satisfy the Klein–Gordon equation equates the Maxwell and field-potential equations with two Dirac equations of the Klein–Gordon mass, and thus one complex Klein–Gordon Maxwell field describes either two real vector fields or two Dirac fields, all of the same mass.     

Silicon transport under rotating and combined magnetic fields in liquid phase diffusion growth of SiGe

The effect of applied rotating and combined (rotating and static) magnetic fields on silicon transport during the liquid phase diffusion growth of SiGe was experimentally studied. 72‐hour growth periods produced some single crystal sections. Single and polycrystalline sections of the processed samples were examined for silicon composition. Results show that the application of a rotating magnetic field enhances silicon transport in the melt. It also has a slight positive effect on flattening the initial growth interface. For comparison, growth experiments were also conducted under combined (rotating and static) magnetic fields. The processed samples revealed that the addition of static field altered the thermal characteristics of the system significantly and led to a complete melt back of the germanium seed. Silicon transport in the melt was also enhanced under combined fields compared with experiments with no magnetic field. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the production and annealing of bombardment induced surface damage on a nickel (110) surface

The production and annealing of damage on a nickel (110) surface has been studied with low energy ion scattering (LEIS) and the results are discussed and compared with previously reported LEED, LEIS and TEM results. It is concluded that the production of damage on crystal surfaces which remain crystalline under ion bombardment may be explained in terms of the nucleation and growth of vacancy clusters. It is found that the damage, as observed by ion scattering, saturates at a level which does not depend on such bombardment conditions as temperature or ion species. The experiments indicate that at saturation, the surface is in a state of dynamic equilibrium in which the rates of creation and loss of surface pits are equal. Expressions are derived to explain both the present and previously reported ion scattering results. The annealing measurements show that two different anneal processes can be distinguished.     

Diffusion approximations to cascade mixing

In two recent studies^{1, 2} of cascade mixing, the process in which energetic ion bombardment can redistribute the atomic components of a multielemental target via recoil processes, a diffusion approximation has been assumed, apparently with signif-icantly different results². It is the purpose of this communication to reveal the close similarity of the two existing treatments and to indicate some important modifications and extensions.