Showing papers by "John B. Pendry published in 1986"
202 citations
141 citations
TL;DR: In this article, O K-edge near-edge absorption spectra for (2 sx 1)O on Cu(110) and accompanying multiple-scattering calculations for models with an unreconstructed substrate and with missing-row and saw-tooth adsorbate-induced reconstructions are presented.
36 citations
TL;DR: It is shown that electrical noise is produced with a $\frac{1}{f}$ spectrum and the scanning tunneling microscope is proposed as the ideal device for observing these fluctuations.
Abstract: We calculate for the first time the distribution of energy widths for Anderson localized states at a surface and show that electrical noise is produced with a $\frac{1}{f}$ spectrum. The distribution has a natural cut-off at widths of $\frac{\ensuremath{\hbar}}{{l}_{c}}$, where ${l}_{c}\ensuremath{\propto}\mathrm{exp}(\frac{{\ensuremath{\delta}}^{\ensuremath{'}2}L}{2})$ and ${\ensuremath{\delta}}^{\ensuremath{'}2}$ measures the disorder; ${l}_{c}$ is typically many hours. The scanning tunneling microscope is proposed as the ideal device for observing these fluctuations.
32 citations
TL;DR: In this paper, the influence of poisons on the local density of states (LDOS) at the CO adsorption site of a nickel (100) cluster was investigated using a Green function method, in which the atoms were described by muffin tin potentials.
32 citations
TL;DR: In this article, the structure of the Rydberg surface states massively weights m ∗ to the free space value, both in a simple model argument and in a multiple scattering treatment of the problem.
21 citations
TL;DR: The influence of S, as a typical electronegative poison for the CO methanation reaction, on catalyst activity for the (111) surfaces of Rh and Ni is considered in this paper.
21 citations
TL;DR: In this article, the authors investigated the problem of diffuse scattering from a simple randomly stepped surface and showed that the angular distribution of diffuse intensity is sensitive to the detailed atomic arrangements within the step.
17 citations
TL;DR: This paper presents a meta-modelling system that automates the very labor-intensive and therefore time-heavy and expensive process of manually cataloging and cataloging individual lines of code in a distributed system.
13 citations
TL;DR: In this paper, it was shown that for systems having highly anisotropic effective mass tensors, localisation occurs for small values or disorder, which enables an analytic theory to be developed.
Abstract: Scaling theories of localisation in disordered materials predict that the conductance and localisation lengths respectively vary as mod E-Ec mod above and below the mobility edge. On the other hand some experiments have observed conductances varying as mod E-Ec mod 12/. In this paper it is shown that for systems having highly anisotropic effective mass tensors, localisation occurs for small values or disorder, which enables an analytic theory to be developed. This anisotropic theory gives an exponent of 1/2. The theory is applicable to n-type silicon provided that inter-valley scattering can be neglected, a result which accords with recent observations. The theory also shows in a natural way how the 1D and 2D limits of localisation theory can be taken by increasing the effective mass in one or two directions. The well known result that all states are localised in 2D is reproduced and can be ascribed to underlying symmetries in the system.
11 citations
TL;DR: In this paper, the formation of Rydberg states at surfaces is discussed, and the binding energy and effective mass of electrons in these surface states are studied, as well as the many-body contributions to lifetimes.
Abstract: The authors discuss the formation of Rydberg states at surfaces, presenting models for the many-body effective potential outside a surface. In the light of these effects the binding energy and effective mass of electrons in these surface states is studied, as well as the many-body contributions to lifetimes. They speculate that the disagreement with experiment of some of the conclusions may be due to resolution problems.
TL;DR: In this article, the authors performed density of states calculations on small clusters to estimate the range of sulphur, phosphorous and carbon poisoning on the Ni(100) surface, and the results showed that sulphur appears to be an even more effective poison than suggested by theory.
TL;DR: In this article, the transmission coefficient of a thin disordered wire varies dramatically with the energy of electrons attempting to diffuse along the wire, which results in noise, in the form of harmonic and intermodulation distortion of the input signal.
Abstract: The transmission coefficient of a thin disordered wire varies dramatically with the energy of electrons attempting to diffuse along the wire. Hence on a microscopic scale the relationship between current and voltage is a highly nonlinear one. This results in noise, in the form of harmonic and intermodulation distortion of the input signal, which has a l/f2 behaviour up to frequencies where hf is comparable with kBT. Analytic expressions are derived for the noise in the limit of weak disorder.
TL;DR: The electron-hole pair contribution to the effective mass of electrons at surfaces is estimated and is shown to be of the order of 1% -2% as mentioned in this paper, which is the same as the single particle contribution.
28 May 1986-Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences
TL;DR: The determination of surface chemical bonds has involved an interplay between theory and experiment as mentioned in this paper and two major techniques, I.e.d. and s.X.a.d., are discussed and some of their limitations analysed.
Abstract: The determination of surface chemical bonds has involved an interplay between theory and experiment. Two major techniques, I.e.e.d. and s.e.X.a.f.s., are discussed and some of their limitations analysed. Finally, I look forward to the development of other methods that will further extend our powers to unravel surface chemical bonding.
TL;DR: In this article, a first principles theory of quantum transport was developed to address the problem of localisation directly without resort to scaling, and it was shown that the localised states behave as extremely long-lived traps with a distribution of lifetimes that leads to the generation of 1/f noise at surfaces and interfaces.
Abstract: Systems with large amounts of disorder have some remarkable properties induced by localisation of the electronic wavefunctions [1, 2]. Current formulations of quantum transport have limited relevance to the case of strong disorder and require the use of scaling theories to apply them to these systems [3]. We have been developing a first principles theory of quantum transport that addresses the problem of localisation directly without resort to scaling [4-6]. The theory reproduces well known results for the d.c. conductivity, but goes beyond that to describe the bandwidth of localised structures when used to convey electrical signals, as well as the non-linearity in the d.c. conductivity implicit in these systems. We have also been able to show that the localised states behave as extremely long lived traps with a distribution of lifetimes that leads to the generation of 1/f noise at surfaces and interfaces.