Non-contact AFM observation of the (3×3) to (3 × 3) phase transition on Sn/Ge(1 1 1) and Sn/Si(1 1 1) surfaces

The (3×3) to (3 × 3) phase transition in Sn/Ge(1 1 1)-(3×3)R30° and Sn/Si(1 1 1)-(3×3)R30° systems was investigated for the first time using a non-contact atomic force microscope (NC-AFM). Observations show the occurrence of the phase transition with small (3 × 3) domains on the Sn/Ge(1 1 1) surface at low temperatures of 78 and 6 K. However, no evidence was found to support the presence of the phase transition for the Sn/Si(1 1 1) system, even when the temperature was lowered to 6 K. The (3 × 3) domains present two patterns, one hexagonal and the other honeycomb, depending on the tip to sample distance.