Intrinsic point defects in half-Heusler AuMnSn

Abstract

Experimental evidences have revealed the existence of intrinsic defects in Half-Heusler AuMnSn (HH-AMS). In this work, using density-functional theory, we explore the energetics, electronic and magnetic properties of intrinsic point defects in HH-AMS crystal compound. The defects considered are antisite, interstice, vacancy and atom swap defects. We find relatively low negative formation energy for Au⇒Mn (Au atom in the Mn position) antisite, Sn⇒Mn antisite and Au interstitial defects, which suggests that they have high possibilities of being formed spontaneously during the crystal growth process. Other types of defects have positive formation energy which may be an indication of their existence in low concentration in the HH-AMS crystal. Furthermore, the Sn⇒Au antisite and Sn interstitial defects change ferromagnetic HH-AMS to a half-metallic ferromagnet which is an important material for spintronics applications.