Re-writable nm-scale patterns were formed on Ge(001) at 80K, which were based upon the transition between c(4 x 2) and p(2 x 2) surface reconstructions induced by a scanning tunnelling microscope. It was found that a negative (-0.8V, 0.5s) sample bias voltage pulse created a c(4 x 2)-reconstructed domain of ~1.6 x 2.0nm2 in a p(2 x 2)-reconstructed region. Applying the negative pulses at appropriate positions, formed an intended pattern of the c(4 x 2) reconstruction. The course of patterning could be monitored by scanning tunnelling microscopy with a small bias voltage (–0.2V) without affecting the written pattern. The whole region could be initialized to the p(2 x 2) by a scan with the bias voltage of +0.8V.

Rewritable Nanopattern on a Ge(001) Surface Utilizing p(2 x 2)-to-c(4 x 2) Transition of Surface Reconstruction Induced by a Scanning Tunnelling Microscope. Y.Takagi, M.Yamada, K.Nakatsuji, F.Komori: Applied Physics Letters, 2004, 84[11], 1925