Self-organized atomic nanowires of noble metals on Ge(001): atomic structure and electronic properties

TL;DR

This paper reviews the atomic structure and electronic properties of noble metal nanowires grown on Ge(001), highlighting their self-organization, metallic conduction, and potential for hosting 1D electron systems.

Contribution

It provides detailed structural and electronic characterization of Pt and Au nanowires on Ge(001), demonstrating atomic control over their properties and growth methods.

Findings

Pt nanowires exhibit metallic conduction at room temperature.

Au nanowires are well separated and show continuous 1D charge density.

Both types of nanowires demonstrate potential for 1D electron systems.

Abstract

Atomic structures of quasi-one-dimensional (1D) character can be grown on semiconductor substrates by metal adsorption. Significant progress concerning study of their 1D character has been achieved recently by condensing noble metal atoms on the Ge(001) surface. In particular, Pt and Au yield high quality reconstructions with low defect densities. We reported on the self-organized growth and the long-range order achieved, and present data from scanning tunneling microscopy (STM) on the structural components. For Pt/Ge(001), we find hot substrate growth is the preferred method for self-organization. Despite various dimerized bonds, these atomic wires exhibit metallic conduction at room temperature, as documented by low-bias STM. For the recently discovered Au/Ge(001) nanowires, we have developed a deposition technique that allows complete substrate coverage. The Au nanowires are extremely well separated spatially, exhibit a continuous 1D charge density, and are of solid metallic conductance. In this review we present structural details for both types of nanowires, and discuss similarities and differences. A perspective is given for their potential to host a one-dimensional electron system. The ability to condense different noble metal nanowires demonstrates how atomic control of the structure affects the electronic properties.