Atomic-scale detection of magnetic impurity interactions in bulk semiconductors

TL;DR

This paper uses ab initio simulations and scanning tunneling microscopy to study atomic-scale magnetic impurity interactions in semiconductors, revealing differences in wave function extension that affect ferromagnetism.

Contribution

It introduces a method to analyze magnetic impurity interactions at the atomic scale in bulk semiconductors using surface passivation and STM techniques.

Findings

Wave functions of 3d impurities in Si are less extended than in GaAs.

Less extended wave functions hinder ferromagnetism in Si.

The approach can be applied to other dilute magnetic semiconductors.

Abstract

We demonstrate on the basis of ab initio simulations how passivated semiconductor surfaces can be exploited to study bulklike interaction properties and wave functions of magnetic impurities on the atomic scale with conventional and spin-polarized scanning tunneling microscopy. By applying our approach to the case of $3d$ transition metal impurities close to the H/Si$(111)$ surface, we show exemplarily that their wave functions in Si are less extended than for Mn in GaAs, thus obstructing ferromagnetism in Si. Finally, we discuss possible applications of this method to other dilute magnetic semiconductors.