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

TL;DR

This study uses first-principles calculations to analyze how Mn impurities affect the structural and magnetic properties of the GaAs(110) surface, revealing local distortions and magnetic interactions.

Contribution

It provides detailed insights into the local distortions and magnetic configurations caused by Mn interstitials on the GaAs(110) surface, which were not previously characterized.

Findings

Mn impurities cause strong local distortions with up to 8% bond length variations.

Interstital Mn induces spin polarization, leading to ferromagnetic Mn-As and antiferromagnetic Mn-Ga configurations.

Distortions propagate up to the third sub-surface layer.

Abstract

We have investigated STM images of the (110) cross-sectional surface of Mn-doped GaAs using first principles total-energy pseudopotential calculations. We focus on configurations with Mn interstitial in the uppermost surface layers. In particular, we have found that Mn impurities, surrounded by Ga or As atoms, introduce in both cases strong local distortions in the GaAs(110) surface, with bond length variations up to 8 % on surface and non-negligible relaxations effects propagating up to the third sub-surface layer. In both cases interstitial Mn induces a spin-polarization on its nearest neighbors, giving rise to a ferromagnetic Mn-As and to antiferromagnetic Mn-Ga configuration.