Physical and chemical properties of bimetallic surfaces

This paper reviews the available data about the structure of bimetallic surfaces where the constituent elements are intermixed at atomic level. These systems include the surface of bulk alloys ('alloy surfaces') and systems resulting from diffusion at metal-metal interfaces ('surface alloys'). All cases where a complete surface crystallographic determination exists are listed and discussed, as well as selected cases where the structural data are not complete but can lead to a model of the atomic structure.

https://iopscience.iop.org/article/10.1088/0034-4885/57/10/001/pdf

The atomic structure of alloy surfaces and surface alloys

The last decade has seen remarkable new developments in the field of low energy electron diffraction (LEED) which are reviewed in the present paper. The arrival of sophisticated and fast techniques for the measurement of diffraction intensities in the early 1980s was a challenge to theory. Its answer was the development of tensor LEED (TLEED) in 1985. It allows the fast calculation of intensities for structures not too far from a certain reference. This made quantitative surface structure analysis approach new frontiers both with respect to structural complexity and-with the help of the routine use of reliability factors-to precision. Simultaneously, the new experimental techniques allowed access to two-dimensional intensity maps, i.e. the measurement of diffuse intensity distributions. Theory could be modified to calculate such distributions and so gave birth to the diffuse LEED technique (DLEED) which allows the retrieval of the local structure in case of disordered adsorption. The basics and the development of both TLEED and DLEED is reviewed. TLEED is the basis for direct methods and is used in effective search procedures for surface structures structurally close to a certain reference. It can also be used to simulate the substitution of surface atoms by different chemical species as well as to account for surface vibrations. In addition to carrying the information about the local structure, DLEED patterns very recently could be successfully interpreted in a holographic sense yielding real space images directly.

https://iopscience.iop.org/article/10.1088/0034-4885/58/6/003/pdf

LEED and DLEED as modern tools for quantitative surface structure determination

Hydrogen detection near surfaces and shallow interfaces with resonant nuclear reaction analysis

Fast LEED intensity calculations for surface crystallography using Tensor LEED

Investigation of surface atom vibrations by tensor LEED

We present a chemical perturbation method for surface-structure determination by low-energy electron diffraction (LEED). It is based on tensor LEED theory and is able to substitute selected surface atoms by other chemical species making full dynamical calculations for the structure unnecessary. The potential of the approach is demonstrated for the determination of the surface stoichiometry of substitutionally disordered alloys, for the switching from one adsorbate species to another, and for the generation of superstructures by substitution of surface atoms by vacancies

R. Döll

Papers

Investigation of surface atom vibrations by tensor LEED

Chemical substitution of surface atoms in structure determination by tensor low-energy electron diffraction

Application of chemical tensor LEED to MoxRe1−x(100) surfaces

Recent advances in LEED surface crystallography

Direct analysis of chemically disordered compounds by inverted tensor LEED