Experimental Observation of Blocked Melting on the Au(111) Surface

The structure of the f.c.c. Au(111) surface was investigated in the temperature range between 300 and 1350 K by the ion channelling and blocking method MEIS. At about 950 K the surface deconstructs. We observed at a critical temperature of (1070 ± 20) K a sudden disordering of the topmost surface layers. The number of visible (111) layers changes dramatically at this temperature. Such a blocked melting behaviour is predicted by the premelting theory and by molecular-dynamics calculations for the Au(111) surface.