The dynamic characteristics of the C defect at 80K were studied by means of sequential scanning tunnelling microscopy. It was found that the C defect frequently transformed into another type of defect: C2LT defect. The reverse, C2LT-toC transformation, was also observed. This implied that the C2LT defect was a metastable state of the C defect. The observed structural transformation was completely different to that observed at room temperature. It was suggested that structural transformation, associated with a change in the phase of the defect, was suppressed at low temperatures because it disturbed the ordering of the surrounding buckled dimers.

Structure Transformation of the C Defects Observed at Low Temperature (80K) K.Hata, R.Morita, M.Yamashita, H.Shigekawa: Japanese Journal of Applied Physics - 1, 1999, 38[6B], 3837-40