Pinned and unpinned step dynamics on vicinal silver (110) surfaces

We present x-ray scattering and scanning-tunneling-microscopy studies of Ag(110) vicinally miscut along the [1̄10] direction. For a clean surface miscut by 1°we find no evidence for phase separation. However, for an impurity concentration of order 0.001 monolayer we find that the pinning of steps results in a phase separation into flat (110) terraces and densely stepped regions. With increasing temperature, the clean surface exhibits a rapid decrease in step-step correlations primarily along the [001] direction. © 1993 The American Physical Society.