Studies of single doping of Mn and Fe in Si to deduce simple guidelines in selecting transition metal elements for growing Si-based spintronic materials

TL;DR

This study uses first-principles calculations to analyze how Mn and Fe dopants affect silicon's structure and magnetism, providing guidelines for developing Si-based spintronic materials.

Contribution

It offers new insights into the effects of transition metal doping in silicon, emphasizing atom size influence and site-dependent properties for spintronic applications.

Findings

Atom size influences local lattice contraction or expansion around dopants.

Dopants at tetrahedral interstitial sites cause expansion only.

Magnetic moments vary depending on dopant type and site.

Abstract

Single dopings of Mn and Fe in Si are investigated using 8-, 64-, and 216-atom supercells and a first-principles method based on density functional theory. Between the two transition metal elements (TMEs), atom sizes play an essential role in determining the contraction or the expansion of neighboring atoms around the TME dopant at a substitutional site. At a tetrahedral interstitial site, there is only expansion. Magnetic moments/TME at the two sites are calculated. Physical origins for these inter-related properties are discussed. A few suggestions about the growth of these Si-based alloys are given.