Self-assembled Pt nanowires on Ge(001): Relaxation effects

Absorption of Pt on the Ge(001) surface results in stable self-organized Pt nanowires, extending over some hundred nanometers. Based on band structure calculations within density functional theory and the generalized gradient approximation, the structural relaxation of the Ge--Pt surface is investigated. The surface reconstruction pattern obtained agrees well with findings from scanning tunneling microscopy. In particular, strong Pt--Pt dimerization is characteristical for the nanowires. The surface electronic structure is significantly perturbed due to Ge--Pt interaction, which induces remarkable shifts of Ge states towards the Fermi energy. As a consequence, the topmost Ge layers are subject to a metal-insulator transition.Comment: 4 pages, 2 figures, final version accepted by Europhys. Lett., minor modifications of the tex

The Effect of Fermented Sour Milk Consumption on the Health Conditions and the Recovery From Diarrhea of Elementary School Pupils

Calpico is a drink made of fermented sour milk cultured with lactic acid bacteria (Lactobacillus helveticus). Calpico drink contains 1010 cells of lactic acid bacteria for one cup serve, although it is not alive. The purpose of this study is to investigate a possible effect of Calpico ingestion on prevention or recovery from diarrhea. The pupils of the 4th grade of two elementary schools were subjected. Pupils were requested to answer the questionnaire about social and health conditions of their own. After measuring body weight, pupils for Calpico group were given 200 ml of one-fifth diluted Calpico every morning at 9 AM. Pupils of control group were given nothing. More over half of pupils who drunk Calpico for one month increased one to two kg of their body weight after test period. The frequency of diarrhea of Calpico group was markedly decreased. It was shown in Jakarta that Calpico ingestion had a dramatically effect on recovery from diarrhea and improvement of health condition noted by the increase of body weight of the pupils

Neutralino Cascades in the (M+1)SSM

In the (M+1)SSM an additional gauge singlet Weyl spinor appears in the neutralino sector. For a large part of the parameter space this approximative eigenstate is the true LSP. Then most sparticle decays proceed via an additional cascade involving the NLSP -> LSP transition, where the NLSP is the non-singlet next-to-lightest neutralino. We present a comprehensive list of all processes, which contribute to the NLSP -> LSP transition, the partial widths and the total NLSP decay rate. We perform a scan of the parameters of the model compatible with universal soft terms, and find that the NLSP life time can be quite large, leading to macroscopically displaced vertices. Our results imply that the signatures for sparticle production in the (M+1)SSM can be very different from the MSSM, and are important for calculations of the abundance of dark matter in this model.Comment: 25 pages (LaTeX2e), 8 figs., explanations adde

Interface relaxation and electrostatic charge depletion in the oxide heterostructure LaAlO3/SrTiO3

Performing an analysis within density functional theory, we develop insight into the structural and electronic properties of the oxide heterostructure LaAlO3/SrTiO3. Electrostatic surface effects are decomposed from the internal lattice distortion in order to clarify their interplay. We first study the interface relaxation by a multi-layer system without surface, and the surface effects, separately, by a substrate-film system. While elongation of the TiO6 octahedra at the interface enhances the metallicity, reduction of the film thickness has the opposite effect due to a growing charge depletion. The interplay of these two effects, as reflected by the full lattice relaxation in the substrate-film system, however, strongly depends on the film thickness. An inversion of the TiO6 distortion pattern for films thinner than four LaAlO3 layers results in an insulating state.Comment: 10 pages, 7 figures, accepted by Europhysics Letter