STM study on the (100) Surface of the Ag-In-Yb 1/1 Cubic Approximant

Scanning tunneling microscopy studies have revealed a periodic step-terrace structure in the (100) surface of the Ag-In-Yb 1/1 cubic approximant. The step height between the large terraces is about 0.73 nm, approximately one-half of the lattice constant, which is consistent with the bcc-like crystalline structure of this crystal. Two small terraces are observed between the adjacent large terraces. High-resolution STM images of the large terrace exhibit a square lattice of protrusions with a lattice constant of about 1.55 nm, which is consistent with the bulk lattice constant. The scanning tunneling microscopy results suggest that the large terraces are associated with the planes that intersect the centers of rhombic triacontrahedral clusters (the building unit of the crystal) and show the highest atomic density along the [100] axis. It is highly likely that the small terraces are related to moderate atomic density planes and are less stable than the large terraces.