X-Ray Standing Waves on Surfaces


Book Description

The x-ray standing wave technique is a sensitive tool for determining the position of atoms within a crystal, adsorbed onto a surface or distributed within the crystal or at the interface. The technique is based on the x-ray standing wave field that arises as a result of the interference of coherently related incident and reflected plane waves and is described by the theory of dynamical diffraction of x-rays. When two coherently related traveling plane waves having the same wavelength pass through each other their superposition results in a standing wave of period D = lambda/2 sin theta; where lambda is the wavelength of the traveling waves, and 2 theta is the relative angle between them. The generation of a standing wave requires both an incident and a reflected wave and the letter can be generated by either Bragg diffraction or total external reflection.




X-ray Standing Wave Technique, The: Principles And Applications


Book Description

The X-ray standing wave (XSW) technique is an X-ray interferometric method combining diffraction with a multitude of spectroscopic techniques. It is extremely powerful for obtaining information about virtually all properties of surfaces and interfaces on the atomic scale. However, as with any other technique, it has strengths and limitations. The proper use and necessary understanding of this method requires knowledge in quite different fields of physics and technology. This volume presents comprehensively the theoretical background, technical requirements and distinguished experimental highlights of the technique. Containing contributions from the most prominent experts of the technique, such as Andre Authier, Boris Batterman, Michael J Bedzyk, Jene Golovchenko, Victor Kohn, Michail Kovalchuk, Gerhard Materlik and D Phil Woodruff, the book equips scientists with all the necessary information and knowledge to understand and use the XSW technique in practically all applications.







X-ray Standing Wave Imaging of Metal Atoms on Semiconductor and Oxide Surfaces


Book Description

The 1/3 monolayer (ML) Sn/Si(III)-(√3 x √3)R30° surface structure has been extensively studied using x-ray standing waves (XSW). The summation of several XSW measured hkl Fourier components results in a three-dimensional, model-independent direct-space image of the Sn atomic distribution. While the image demonstrates that the Sn atoms are located at Si(111) T4-adsorption sites, it alone cannot determine whether the Sn atomic distribution is flat or asymmetric. However, conventional XSW analysis can make this distinction, concluding that one-third of the Sn atoms are located 0.26 A higher than the remaining two-thirds. This "one up and two down" distribution is consistent with the vertical displacements predicted by a dynamical fluctuations model. A second sample prepared in a slightly different manner exhibits the same long-range surface symmetry, but a direct space image clearly reveals that a significant fraction of the Sn atoms in the second surface have substituted for Si atoms in the bottom of the Si surface bilayer.













The X-ray Standing Wave Technique


Book Description

The X-ray standing wave (XSW) technique is an X-ray interferometric method combining diffraction with a multitude of spectroscopic techniques. It is extremely powerful for obtaining information about virtually all properties of surfaces and interfaces on the atomic scale. However, as with any other technique, it has strengths and limitations. The proper use and necessary understanding of this method requires knowledge in quite different fields of physics and technology. This volume presents comprehensively the theoretical background, technical requirements and distinguished experimental highlights of the technique. Containing contributions from the most prominent experts of the technique, such as Andre Authier, Boris Batterman, Michael J Bedzyk, Jene Golovchenko, Victor Kohn, Michail Kovalchuk, Gerhard Materlik and D Phil Woodruff, the book equips scientists with all the necessary information and knowledge to understand and use the XSW technique in practically all applications.




Modern Techniques of Surface Science


Book Description

Revised and expanded second edition of the standard work on new techniques for studying solid surfaces.




X-Ray and Neutron Dynamical Diffraction


Book Description

This volume collects the proceedings of the 23rd International Course of Crystallography, entitled "X-ray and Neutron Dynamical Diffraction, Theory and Applications," which took place in the fascinating setting of Erice in Sicily, Italy. It was run as a NATO Advanced Studies Institute with A. Authier (France) and S. Lagomarsino (Italy) as codirectors, and L. Riva di Sanseverino and P. Spadon (Italy) as local organizers, R. Colella (USA) and B. K. Tanner (UK) being the two other members of the organizing committee. It was attended by about one hundred participants from twenty four different countries. Two basic theories may be used to describe the diffraction of radiation by crystalline matter. The first one, the so-called geometrical, or kinematical theory, is approximate and is applicable to small, highly imperfect crystals. It is used for the determination of crystal structures and describes the diffraction of powders and polycrystalline materials. The other one, the so-called dynamical theory, is applicable to perfect or nearly perfect crystals. For that reason, dynamical diffraction of X-rays and neutrons constitutes the theoretical basis of a great variety of applications such as: • the techniques used for the characterization of nearly perfect high technology materials, semiconductors, piezoelectric, electrooptic, ferroelectric, magnetic crystals, • the X-ray optical devices used in all modem applications of Synchrotron Radiation (EXAFS, High Resolution X-ray Diffractometry, magnetic and nuclear resonant scattering, topography, etc. ), and • X-ray and neutron interferometry.