‘‘Magic’’ vicinal surfaces stabilized by reconstruction

We have studied the structure and surface energetics of vicinals of Au(100) and Au(111), using a well-tested many-body force model for gold and molecular dynamics. Surface reconstruction by in-plane contraction---known to occur on Au(100) and Au(111)---takes place on terraces between steps, causing the appearance of particularly favored ``magic'' orientations whenever the terrace width roughly contains an integer number of reconstruction cells. This phenomenon has implications on the faceting behavior of these surfaces, and explains recent observations of ``locked'' distances between steps.