Terrace-width distributions and step-step repulsions on vicinal surfaces: symmetries, scaling, simplifications, subtleties, and Schrodinger

For more than three decades, measurement of terrace width distributions (TW Ds) of vicinal crystal surfaces have been recognized as arguably the best w ay to determine the dimensionless strength (A) over tilde of the elastic re pulsion between steps. For sufficiently strong repulsions, the TWD is expec ted to be Gaussian, with (A) over tilde varying inversely with the squared variance. However, there has been a controversy over the proportionality co nstant. From another perspective the TWD can be described as a continuous g eneralized Wigner distribution (CGWD) essentially no more complicated than a Gaussian but a much better approximation at the few calibration points wh ere exact solutions exist. This paper combines concisely the experimentally most useful results from several earlier papers on this subject and descri bes some advancements that are in progress regarding numerical tests and in using Schrodinger-equation formalism to give greater understanding of the origin of the CGWD and to give hope of extensions to more general interacti on potentials between steps. There are many implications for future experim ents. (C) 2001 Elsevier Science B.V. All rights reserved.