OBSERVATION OF AN ADLAYER-DRIVEN SUBSTRATE RECONSTRUCTION IN CU-PT(111)

An unusual strain relaxation mechanism has been observed during the gr owth of ultrathin Cu films on Pt(lll) at a substrate temperature of 45 0 K. After the completion of a pseudomorphic first Cu monolayer, the P t substrate undergoes a reconstruction which is visible in the pseudom orphic Cu overlayer. Using in situ helium atom scattering, interlayer mass transport is observed as ad-atoms are incorporated into the subst rate. Scanning tunneling microscopy measurements allow us to label the substrate reconstruction as being similar in nature to the ''star'' n etwork of the reconstructed Pt(111) surface. [S0163-1829(98)52840-8].