Self-organization on surfaces: foreword

Abstract

After decades of work, the growth of continuous thin films, i.e., two-dimensional structures, is progressively becoming a technological issue more than a field of fundamental research. Incidentally self-organization of nanostructures on surfaces is now an important field of research, i.e., structures of dimensionality one or zero, with a steep rise of attention in the past five years. Whereas self-organization was initially motivated by potential applications, it has up to now essentially contributed to the advancement of fundamental science in low dimensions, as model systems could be produced that could not have been fabricated by lithography. This Special Issue aims at giving a cross-community timely overview of the field. The Issue gathers a broad panel of articles covering various selforganization mechanisms, specific structural characterization, physical properties, and current trends in extending the versatility of growth. The materials mostly covered here are semiconductors and magnetic materials. To cite this article: O. Fruchart, C. R. Physique 6 (2005). RésuméAprès plusieurs décennies d'intense activité, la croissance des couches minces, c.à.d. de systèmes de dimension deux, tend progressivementà devenir plus une question de maîtrise technologique qu'un sujet de recherche fondamentale. Dans le même temps l'auto-organisation aux surfaces de nanostructures, c.à.d. de dimensionnalité un voire zéro, prend une importance grandissante, tout spécialement depuis cinq ans. Alors que l'auto-organisatioń etait initialement motivée par des perspectives d'applications, elle a pour l'instant essentiellement contribuéà l'acquisition de nouvelles connaissances de physique fondamentale en basse dimension, puisque des systèmes modèles ont puêtre fabriqués, qui n'auraient puêtre obtenus par la technique conventionnelle de structuration qu'est la lithographie. Ce dossier thématique a pour objectif de proposer un aperçu actuel de l'auto-organisation, en essayant de dépasser les frontières de communautés. Ainsi sont rassemblées des contributions traitant de divers mécanismes physiques de l'auto-organisation, de techniques de caractérisation spécifiques, de propriétés physiques, et des nouvelles approches poursuivies pour augmenter la versatilité des procédés de croissance. Les matériaux couverts ici sont essentiellement les semiconducteurs et les matériaux magnétiques. Pour citer cet article : O. Fruchart, C. R. Physique 6 (2005).

Role of step-flow advection during electromigration-induced step bunching

“…Using Eqs. (11,12,13), we obtain the analytical expression for the boundary lines η c (s) separating the stable and the step bunching regions in the (s, η) plane: In addition, one shows that step-pairing instability becomes the most unstable mode for η p = v 0 + a(B 2 − 3B 3 )/B 1 . The stability diagram representing the boundaries between the stable, and unstable regions is shown in Fig.…”

“…Using Eqs. (11,12,13), we obtain the analytical expression for the boundary lines η c (s) separating the stable and the step bunching regions in the (s, η) plane: In addition, one shows that step-pairing instability becomes the most unstable mode for…”

“…A few ways to reach this goal are currently under investigation, such as imposing a net atomic flux (evaporation/deposition), using elastic stresses or applying a constant electrical field inducing an adatom drift (surface electromigration). Combinations of these methods allow extra flexibility [6,12]. Surface electromigration was first observed by Latyshev and co-authors [13], and an early theory proposed by Stoyanov [14].…”

Magnetism in reduced dimensions

“…Instead, when this field has been explored in the last decade, one used e.g. clusters fabricated by physical means [23], or epitaxial selforganization (SO) at surfaces [24,25]. The disentanglement of magnetoelastic and true Néel anisotropy is even more difficult than for thin films, given the complexity of geometry and strain, and in most cases because of the distribution of local environments (loss of the small unit cell).…”