Cu induced morphology changes at Pb/Si (1 1 1) interface: Separation of “5 × 5”-Cu structure into individual domains

► Deposition of copper onto Pb/Si (1 1 1) interface changes the original Pb-Si structures. ► New objects of hexagonal form appear on √3 × √3R30°-Pb phase upon temperature treatment. ► Formation of the copper silicides below the inert Pb layer is assumed. ► The hexagonal objects are single domains of “5 × 5”-Cu phase separated by the border made of Pb atoms.