IMPURITY TRAPPING EFFECTS IN THE LOCALIZATION OF MUONS IN SOLIDS

Muon spin rotation ( mu SR) experiments are now regularly used to study solids and solid-state processes. The interpretation of mu SR data is usually based on a 'standard' picture in which the muons localise randomly in the solid, and then diffuse, possibly encountering impurities. There remain some important cases where no satisfactory interpretation results. For some of these anomalous systems the authors propose an alternative picture in which the two different factors are the importance of metastable (free muon) excited states, and the role of impurities in causing localisation. They show this allows a possible explanation of results for Al:Mn and demonstrate that elastic strain fields of defects may be a major factor in influencing localisation. They also propose a new mechanism for delayed self-trapping

Perspectives on information and supply chains within investment banking

Supply chain concepts are usually confined to industries where there are core sourcing, manufacture and delivery processes. These industries are usually to be found within the industrial products, aerospace, automotive, chemical and pharmaceutical sectors. Supply Chain Management (SCM) concepts, have not necessarily been associated with financial services, apart from concepts of information management and process flow, in the loosest sense. This paper attempts to describe how supply chain concepts are very much an inherent part of the financial services process landscape, with particular reference to the field of investment banking. In doing so, the paper explores IT/IS issues impacting within the investment banking industry, focussing on the requirements for efficient distribution of sales and research data. Following this, the authors extend concepts of supply chain and information management, to realise the concept of an Investment Banking Information Supply Chain (IBISC)

ELECTRONIC-STRUCTURE OF SELF-TRAPPED EXCITON IN SODIUM-CHLORIDE

The electronic structure of the relaxed exciton is investigated using a Hartree-Fock method. The model concentrates on a cluster of two sodium and two chlorine ions surrounded by an array of point charges. The excited states of the exciton and the associated transitions are discussed. The results are compared with experiment and with the phenomenological models proposed earlier workers. A number of features are confirmed, giving a general picture close to that of Kabler and his co-workers. One problem emerges, since it proves possible to understand the sigma luminescence or the pi luminescence, but not both at present. Possible reasons are discussed. In other respects, there is good agreement with experiment, especially for the optical transitions starting from the lowest triplet state of the exciton

It's written in the cloud: The hype and promise of cloud computing

Purpose of paper: This viewpoint discusses the emerging IT platform of Cloud Computing and discusses where and how this has developed in terms of the collision between internet and enterprise computing paradigms – and hence why cloud computing will be driven not by computing architectures but more fundamental ICT consumption behaviours. Design/methodology/approach: The approach has been based upon the discussion and recent developments of Software as a Service (SaaS) and associated ICT computing metaphors and is largely based upon the contemporary discussion at the moment of the impact of social, open source and configurable technology services. Findings: It is suggested that whilst cloud computing and SaaS are indeed innovations within ICT, the real innovation will come when such platforms allow new industries, sectors, ways of doing business, connecting with and engaging with people to emerge. Thus looking beyond the technology itself. Research limitations/applications: Author viewpoint only, not research based. Practical applications: Brings together some of the recent discussions within the popular as well as business and computing press on social networking, open source and utility computing. Social implications: Suggests that cloud computing can potentially transform and change the way in which IS and IT are accessed, consumed, configured and used in daily life. Originality / value of paper: Author viewpoint on a contemporary subject

Making tracks in metals

Swift heavy ions lose energy primarily by inelastic electronic scattering and, above an energy threshold, electronic losses result in damage to the lattice. Such high energy radiation is beyond the range of validity of traditional cascade simulations, and predictive damage calculations are challenging. We use a novel methodology, which combines molecular dynamics with a consistent treatment of electronic energy transport and redistribution to the lattice, to model how swift heavy ions form damage tracks. We consider a range of material parameters (electron-phonon coupling strength, thermal conductivity and electronic specific heat) and show how these affect the maximum lattice temperature reached and the extent of residual damage. Our analysis also suggests that fission tracks may form in alloys of archaeological interest

The challenges of nanostructures for theory

It is tempting to believe that modelling in nanotechnology is much the same as that for conventional solid-state physics. However, important areas of nanotechnology address different systems. The mechanics of DNA (for instance) resembles spaghetti more than silicon, the statistical physics needed is often not carrier statistics, and the role of viscosity (the low Reynolds number limit) is not always the familiar one. The idea of equilibrium may be irrelevant, as the kinetics of nonequilibrium (perhaps quasi-steady state) can be crucial. Even when the issues are limited to nanoscale structures (rather than functions), there is a complex range of ideas. Some features, like elasticity and electrostatic energies, have clear macroscopic analogies, but different questions emerge, such as the accuracy of self-organisation. Others concepts like epitaxy and templating are usually micro- or mesostructural. Some of the ideas, which emerge in modelling for the nanoscale, suggest parallels between molecular motors and recombination enhanced diffusion in semiconductors. (C) 2002 Elsevier Science B.V. All rights reserved

NONRADIATIVE-TRANSITIONS IN SEMICONDUCTORS

Non-radiative transitions affect many aspects of semiconductor performance. Normally they reduce device efficiency by suppressing luminescence, creating defects, reducing carrier lifetimes, or enhancing diffusion during operation. The present review surveys both the theoretical and practical understanding of non-radiative transitions. It includes general theoretical results and the associated ideas, with the emphasis on phonon-induced and defect Auger processes. Most of the purely formal aspects are omitted, but the points of principle where uncertainties remain are discussed. The review also covers the relation between basic theoretical studies and practical applied work on device degradation. This includes a description of the atomic processes involved in the more important mechanism of device deterioration and the theoretical understanding of the mechanism of these underlying processes. Finally, there is a survey of models proposed for 'killer' centres