Scanning tunnelling microscopy study of palladium on stepped Cu(210) surfaces: chemical contrast and room-temperature tip-induced motion

The chemical contrast and tip-induced motion of palladium on stepped Cu(210 ) surfaces at room temperature have been studied by scanning tunnelling mic roscopy (STM). Contrast inversion is shown to be useful for chemical-sensit ive imaging and features such as fringing can be resolved. Step edges and k inks are shown to be thermodynamically more stable palladium adsorption sit es. Tip-induced motion of palladium adatoms on Cu(210) at 300 K has been de monstrated with a threshold gap resistance of 20-50 M Ohm. Annealing the pa lladium-covered surface to 600-700 K results in the ejection of copper atom s to form crystalline copper islands which lie across the substrate steps w ith their [110] axes aligned to the [001] substrate axis. (C) 1999 Elsevier Science B.V. All rights reserved.