The In/Si(111) system reveals an anisotropy in the electrical conductivity and is a prototype system for atomic wires on surfaces. We use this system to study and tune the interwire interaction by adsorption of oxygen. Through rotational square four-tip transport measurements, both the parallel $\left({\sigma }_{\left|\right|}\right)$ and perpendicular $\left({\sigma }_{\perp }\right)$ components are measured separately. The analysis of the I(V) curves reveals that ${\sigma }_{\perp }$ is also affected by adsorption of oxygen, showing clearly an effective interwire coupling, in agreement with density-functional-theory-based calculations of the transmittance. In addition to these surface-state mediated transport channels, we confirm the existence of conducting parasitic space-charge layer channels and address the importance of substrate steps by performing the transport measurements of In phases grown on Si(111) mesa structures.

• Received 29 May 2015
• Revised 10 July 2015

DOI:https://doi.org/10.1103/PhysRevB.92.085426