Signatures of Dirac fermion-mediated magnetic order

TL;DR

This paper demonstrates how magnetic order mediated by Dirac fermions can be observed at the atomic scale in topological states, revealing dependencies on adatom properties and Fermi level, with implications for spin engineering.

Contribution

It provides the first experimental evidence of Dirac fermion-mediated magnetic order at extremely dilute adatom concentrations using STM and atomic deposition.

Findings

Signatures of magnetic order depend on adatom magnetic anisotropy.

Magnetic order critically depends on the Fermi level position.

Atomic-scale control enables new spin engineering possibilities.

Abstract

The spin-momentum locking of topological states offers an ideal platform to explore novel magneto-electric effects. These intimately depend on the ability to manipulate the spin texture in a controlled way. Here, we combine scanning tunneling microscopy with single atoms deposition to map the evolution of topological states under the influence of different magnetic perturbations. We obtain signatures of Dirac fermion-mediated magnetic order for extremely dilute adatoms concentrations. This striking observation is found to critically depend on the single adatoms magnetic anisotropy and the position of the Fermi level. Our findings open new perspectives in spin engineering topological states at the atomic scale and pave the way to explore novel spin-related topological phenomena with promising potential for applications.