SUBSURFACE ISLANDS AND SUPERSTRUCTURES OF CU ON PB(111)

A new growth mode, namely subsurface island growth, has been identifie d by means of scanning tunneling microscopy. When Cu is deposited on P b(111), 3D-Cu islands with a thickness between 1 and 11 layers are imm ersed several layers deep into the Pb substrate. The Cu islands, which can be classified in four different types, are furthermore covered by a monatomic Pb film. On flat Cu islands, this Pb film shows a corruga tion that is strongly dependent on the number of Cu layers beneath. Si ngle Cu layers were found to form a new type of Cu-Pb superstructure i slands.