91福利

Erosion is at the origin of remarkable examples of self-organised patterns in nature such as the ripples and dots that are observed on sand dunes due to the action of wind on the sand bed. At the nanoscale, similar structures can be formed by ion beam erosion. The relation between macroscale aeolian and nanoscale ion induced patterns is not only limited to a morphological resemblance: similar concepts serve to describe their dynamics. Indeed, continuum models for surfaces under ion beam sputtering have been developed in close analogy to the hydrodynamic models used to describe the dynamics of granular matter [1,2].

Ion beam eroded surfaces represent a paradigmatic case of sustained non-equilibrium dynamics governed by the complex interplay between the mechanisms that tend to roughen or smooth the surface. X-ray scattering techniques have been extensively used to study, in situ, the evolution of ensemble averaged quantities such as ordering and roughness, during the sputtering process [3]. However, obtaining information about the dynamics during ion beam erosion is challenging. In this talk, I shall present our grazing incidence coherent X-ray scattering results on the self-organisation dynamics of GaSb(001) surfaces during normal incidence ion beam erosion [4]. Our work provides a novel insight into the erosion dynamics and opens new perspectives for the understanding of self-organisation mechanisms.

[1] J. Muñoz-García et al. in “Toward Functional Nanomaterials”, Lecture Notes in Nanoscale Science & Technology 5, Springer, Berlin (2009)

[2] M. Castro et al.; Phys. Rev. Lett. 94, 016102 (2005)

[3] D. Carbone et al.; J. Phys.: Cond. Matter 21, 224007 (2009)

[4] O. Bikondoa et al.; Sci. Reports 3, 1850 (2013)