Atomic structure of Mn wires on Si(001) resolved by scanning tunneling microscopy

TL;DR

This study reveals the atomic structure of manganese wires on Si(001) surfaces, showing asymmetric features and interactions with silicon dimers, using high-resolution STM and density functional theory simulations.

Contribution

It provides a detailed atomic model of Mn wires on Si(001), highlighting the asymmetric structure and the role of Mn trimers, which was not previously understood.

Findings

Mn forms asymmetric wires on Si(001) at submonolayer coverage.

The atomic configuration involves Mn trimer units explaining observed asymmetries.

Comparison with DFT simulations confirms the proposed atomic structure.

Abstract

At submonolayer coverage, Mn forms atomic wires on the Si(001) surface oriented perpendicular to the underlying Si dimer rows. While many other elements form symmetric dimer wires at room temperature, we show that Mn wires have an asymmetric appearance and pin the Si dimers nearby. We find that an atomic configuration with a Mn trimer unit cell can explain these observations due to the interplay between the Si dimer buckling phase near the wire and the orientation of the Mn trimer. We study the resulting four wire configurations in detail using high-resolution scanning tunneling microscopy (STM) imaging and compare our findings with STM images simulated by density functional theory.