The phase in the alternation of up and down atoms along the chain shifts at type-B boundary between π-bonded chain 2 x 1 reconstructed domains. However, no shift was observed at some domain boundaries in empty state scanning tunnelling microscope images. The no shift was attributed to the domain boundary between Pandey’s original chain-right reconstruction and its chain-left isomer.

Chain-Left Isomer of the π-Bonded Chain Reconstruction at the Ge{111}2 x 1 Surface. H.Hirayama, N.Sugihara, K.Takayanagi: Physical Review B, 2000, 62, 6900-3