Surface stress as a driving force for interfacial mixing

Displacive adsorption of As on vicinal Si(001) surfaces has in the past been attributed to reduction of step-related (extrinsic) surface stress. Here we show images of As adsorption on flat Si(001), obtained with in situ low-energy electron microscopy, and with scanning tunneling microscopy. We find displacive adsorption even on micrometer-sized terraces, on which steps play no significant role. These new results reveal the role of intrinsic surface stress as a driving force for interfacial mixing. © 1992 The American Physical Society.