Does one-dimensional (1D) adatom and cluster diffusion of Pt on the Pt(110)-(1 × 2) surface lead to 1D ripening?

Abstract

The technique of scanning tunnelling microscopy (STM) uniquely allows dynamic processes on surfaces to be followed directly in real space and at atomic resolution. Results for the surface diffusion of Pt adatoms and clusters on the anisotropic, missing row reconstructed Pt(110)-(1×2) surface are briefly reviewed. Mass transport in this system is entirely one-dimensional (ID) since, at low adatom coverage, atoms and clusters are confined to the missing row troughs. In this paper, we therefore address the question if Pt/Pt(110)-(1×2) is a ID model system to study late stage growth phenomena such as island ripening? From STM measurements, we quantify the morphology changes resulting from annealing a surface configuration with small ID Pt islands in the missing row troughs to temperatures in the interval 369-395 K. Interestingly, the resulting increase in island sizes (ripening) cannot be accounted for by the known island and adatom mobilities within a 1D model. An explanation is provided from dynamic, time-resolved 'STM-movies' that directly reveal two novel island-mediated mechanisms for inter-trough mass transport which cause the Pt/Pt( 110)-(1×2) system not to be purely 1D at the higher surface coverage used in the annealing experiments. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.