Extended X-Ray Reflectivity Analysis of Si(111)7×7

Abstract

A number of new results are emerging from the various techniques for measurement of surfaces using X-ray and neutron scattering methods, as witnessed by the program of this conference. With many names (and thankfully few acronyms) currently in use for these methods, it can be helpful to summarise them according to the regions of reciprocal space they refer to, as we attempt to do in Fig 1. This forms a useful guide to evaluating the level of information attained in each experiment, with regard to resolution of detail and its direction. The principal distinction is between the reflectivity (Q_I ≈ 0) and diffraction (Q_I >> 0) regions; further subdivisions apply when Q⊥ ≈ 0 or not, as shown. A finer distinction could have been made between the analysis of crystal truncation rods (“integer order” diffraction) and superstructure reflections (fractional orders), but we chose not to show this.