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 microscopy (STM). Contrast inversion is shown to be useful for chemical-sensitive imaging and features such as fringing can be resolved. Step edges and kinks are shown to be thermodynamically more stable palladium adsorption sites. Tip-induced motion of palladium adatoms on Cu(210) at 300 K has been demonstrated with a threshold gap resistance of 20-50 MΩ. Annealing the palladium-covered surface to 600-700 K results in the ejection of copper atoms to form crystalline copper islands which lie across the substrate steps with their [110] axes aligned to the [001] substrate axis