Fe adatoms along Bi lines on H/Si(001): Patterning atomic magnetic chains

TL;DR

This study uses spin-density functional calculations to explore the stability, electronic, and magnetic properties of Fe adatoms forming atomic chains along Bi lines on H/Si(001), revealing stable antiferromagnetic chains with half-metallic behavior.

Contribution

It demonstrates the formation of stable, antiferromagnetically coupled Fe atomic chains along Bi nanolines with significant magnetic anisotropy and half-metallic electronic structure.

Findings

Fe adatoms form stable one-dimensional chains near Bi lines.

The Fe chains exhibit antiferromagnetic coupling with a magnetic moment of 1.5 μB.

The electronic structure shows half-metallic behavior.

Abstract

The stability, electronic and magnetic properties of Fe atoms adsorbed on the self-assembled Bi-dimer lines nanostructure on the H/Si(001) surface are addressed by spin-density functional calculations. Our results show that Fe adatoms are much more stable on sites closer to the Bi nanolines being able to form one-dimensional atomic arrays. The most stable structure occurs on a missing dimer line aside the Bi dimers, which corresponds to an array with distances between Fe adatoms of about 8 Ang. In this array the irons are coupled antiferromagnetically with spin magnetic moment of about 1.5 Bohr magnetons per Fe atom, whereas the coupling exchange interactions is found to be of 14.4 meV. We also estimate a large magnetic anisotropy energy for the Fe adatom of about 3 meV/atom. In addition, the electronic band structure of the Fe array at the most stable structure shows a magnetic half-metal behavior.