We use scanning tunneling microscopy to investigate the interactions between atomic chains, of two different types, formed by the adsorption of submonolayer Au onto a stepped Si surface. The first chain consists of a double row of Au atoms. The second is a single row of Si dangling bonds at the edges of the steps. The two chains are interspersed and hence each could, in principle, influence the other structurally as well as electronically. However, we find this interaction to be highly unidirectional: The Au chains modulate the Si chains, breaking their parity and lending them directionality, while the Si chains leave the Au chains unaffected.

• Received 10 July 2017

DOI:https://doi.org/10.1103/PhysRevB.96.081406