fig1

Figure 1. (A) Schematic diagram of the epitaxial growth of Sn on the surface of Al(111). (B and C) Typical scanning tunneling microscopy (STM) images of as-prepared surfaces showing the coexistence of bare substrate and sub-monolayer Sn-I phase [(2 V, 50 pA for (B) and 1 V, 50 pA for (C)]. (D) Enclosed STM image of Sn-I phase, showing two lattice directions with their unit cell marked by black rhombuses (0.5 V, 50 pA). (E) The STM image (1 V, 50 pA) of a selected area after scanning at an extremely low sample bias which induced scratches on the surface of Sn-I phase. (F and G) Height profiles along the corresponding lines in (C) (blue) and (E) (black).