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The electronic structure of quasiperiodic lattices is studied. An alloy theory, including short-range order effects, is used to approximate Fibonacci and Thue–Morse lattices. Short-range order is treated by embedding small clusters in an alloy that itself incorporates a two-site approximation, and...
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McDowell's 1985 electronic bath theory of charge transfer is used to investigate the effect of varying surface temperature on the process of ion scattering from a solid surface. As a specific example, the system of Na+ scattered from W is modeled. The neutralization probability is found to have a si...
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The introduction of non-orthogonal atomic orbitals, into the tight-binding approximation, gives rise to the existence of overlap terms in electronic band-structure calculations. In contrast to the zero-overlap situation, it is helpful to employ a tensorial Green-function approach to access the surfa...
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A theoretical study of the electronic structure of the (111) surfaces of CoSi2 and NiSi2 and their interfaces with Si has been carried out with particular attention paid to the existence of localized states. A Green function method has been used within the empirical tight-binding approximation to ca...
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A tight-binding investigation is performed of the electronic structure of a semi-infinite monatomic chain, whose atomic orbitals are assumed to be non-orthogonal, so that the effects of overlap can be taken into account. In addition to markedly modifying the bulk band-edges, the presence of overlap ...
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A brief overview is given of the theory of surface-ion neutralization (SIN) by highlighting studies from the pioneering days to the present time. Emphasis is placed on the 1-electron time-dependent Newns-Anderson (TDNA) model, which has played such a key role in studying resonance charge transfer. R...
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A methodology of transmission through two-dimensional tight-binding lattices is presented. The theory is formulated in terms of matrix algebra and the relationships between the matrices are examined in detail. The features specific to tight-binding systems are contrasted to those for more general tr...
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We present a theoretical model for studying the effects of an electromagnetic (laser) field on the process of neutralization of an ion during scattering by a surface. The model is part of a many-electron theory within the framework of a time-dependent version of the Anderson-Newns model. Where we sp...
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A many-electron theory of resonant charge transfer, originally formulated for the scattering of an atom with an empty valence orbital from a surface, is extended to treat the case where the valence orbital is initially occupied by one or two electrons. The scattering of He and He+ from the Si(001) s...
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The electron transmission properties of a semiconducting wire are investigated via the tight-binding approximation. The wire is modeled as a chain of sp-hybrid orbitals, including overlap effects. The transmission probability is calculated using the tensorial Green function method. An impurity in th...
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We consider the problem of comparing the suitability of various magnetic lattices for the spin polarization of neutrons. To do this, we use a discrete model to construct measures of transmission through one-dimensional lattices. We examine the model for non-periodic lattices that are generated from ...
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A dynamical-systems model of plasma glucose concentration, andits regulation by insulin and glucagon, is described, as pertains to types 1 and2 diabetes. The hyperglycemic case is seen to be dependent only on insulinconcentration, while the hypoglycemic case requires consideration of both in-sulin a...
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The theory of resonant charge transfer is refined to deal with the overlap between the ion orbital and substrate orbitals, to introduce new numerical methods for estimating the interaction and most significantly to construct pseudo-states to model realistic densities of states for substrates.
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This paper studies the effect of varying substrate temperatures on the resonant charge-transfer process between a scattered particle and a solid surface. Two possible mechanisms for an effect are considered: (1) coupling of the transferring electron to the thermal motion of the target atom on the su...
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An empirical tight-binding (ETB) approach combined with a Green's-function (GF) method has been employed to investigate the electronic structure of the Si(111) and arsenic-passivated Si(111) surfaces. An accurate silicon band structure has first been developed keeping up to second-nearest-neigh...
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An information theoretic measure is introduced to compare the disorder in non-periodic sequences. It is shown that the measure correctly distinguishes quasiperiodic and aperiodic sequences which have been deduced from earlier studies using diffraction patterns, although it is often necessary to use ...