Fig. 4

STM images of lateral manipulation steps of polycyanine chains. The manipulations were performed with the STM tip at the positions and along the directions of the white arrows. The initial locations of the chains are indicated by the dashed lines. a, b Manipulation of a short isolated chain moves the entire chain across the surface, while retaining its orientation. b, c Additional manipulation of this chain leads to further displacement and formation of a bent with a bright protrusion (yellow arrow in c, which is attributed to an uplifted chain segment (see Supplementary Fig. 8). These protrusions are induced by sterical hindrance and also occur at sharp bends, that is, when a chain changes its orientation, as marked by yellow arrows in Fig. 3a. d–f Manipulation of a longer chain, resulting in the formation of bends with related protrusions, but no rupture of the chain. g–i Reversible manipulation of a chain anchored at both ends. The induced protrusions appearing in h are reversed by pushing in the opposite direction (see i). Tunneling parameters: a–f, U = −3.6 V, I = 0.09 nA; g–i, U = −3.7 V, I = 0.12 nA. All the scale bars are 10 nm