Structural, electronic and magnetic properties of Mn-doped GaAs(110) surface

TL;DR

This study uses first-principles calculations to explore how Mn doping affects the structural, electronic, and magnetic properties of the GaAs(110) surface, revealing local distortions, half-metallicity, and distinguishable STM patterns.

Contribution

It provides detailed insights into the local effects of Mn doping on GaAs(110) surfaces, including magnetic configurations and STM image predictions, which were not previously characterized.

Findings

Mn induces local lattice distortions up to 3%.

Surface electronic structure remains half-metallic or nearly so.

Distinct STM patterns can identify Mn configurations.

Abstract

First principles total-energy pseudopotential calculations have been performed to investigate STM images of the (110) cross-sectional surface of Mn-doped GaAs. We have considered configurations with Mn in interstitial positions in the uppermost surface layers with Mn surrounded by As (Int$_{As}$) or Ga (Int$_{Ga}$) atoms. The introduction of Mn on the GaAs(110) surface results in a strong local distortions in the underlying crystal lattice, with variations of interatomic distances up to 3% with respect to unrelaxed ones. In both cases, the surface electronic structure is half-metallic (or \emph{nearly} half metallic) and it strongly depends on the local Mn environment. The nearby Mn atoms show an induced spin-polarization resulting in a ferromagnetic Mn--As and antiferromagnetic Mn--Ga configuration. The simulation of the STM images show very different pattern of the imaged Mn atom, suggesting that they could be easily discerned by STM analysis.