The morphologies and surface dynamic processes on RuO2 single-crystal substrates were studied using scanning tunnelling microscopy under non-vacuum conditions. The as-grown oxide surfaces show a variety of constructs and aggregations of a-top atoms that formed secondary microstructures with no distinct periodicity. Atomically resolved images captured on adjacent terraces of the same sample indicate differences in a-top atomic arrangements on a single-crystal surface. After annealing an as-grown sample in air at ≈450C for 2h, the scanning tunnelling microscopy images show an ordered, long-range surface reconstruction along the c-axis of the crystal lattice. Combined, this morphological diversity and structural rearrangement suggest motion and clustering of the surface atoms at elevated temperatures.

Morphology and Surface Reconstruction on RuO2 Single Crystals. S.B.Basame, D.Habel-Rodriguez, D.J.Keller: Applied Surface Science, 2001, 183[1-2], 62-7