Energetic stability, electronic structure, and magnetism in Mn-doped silicon dilute magnetic semiconductors

Abstract

First-principles study on the energetic stability, electronic structure, and magnetic coupling in Mn-doped silicon with various configurations has been performed systematically. The results show that the poly-Mn atoms prefer to aggregate in the Mn-doped silicon dilute magnetic semiconductor. It is found that the tetrahedral interstitial Mn $({\text{Mn}}_{T})$ atoms assemble together via an intervening substitutional Mn $({\text{Mn}}_{\text{Si}})$ ion, subsequently forming the generally favored ${\text{Mn}}_{T}{\text{-Mn}}_{\text{Si}}{\text{-Mn}}_{T}$-type complexes. The dominant $d\text{\ensuremath{-}}d$ exchange interactions between the ${\text{Mn}}_{\text{Si}}$ and ${\text{Mn}}_{T}$ make all Mn ions in the ${\text{Mn}}_{T}{\text{-Mn}}_{\text{Si}}{\text{-Mn}}_{T}$ structures interact ferromagnetically with each other.