Chemical trend in the electronic structure of Fe-doped III-V semiconductors and possible origin of ferromagnetism: A first-principles study

Abstract

The electronic structures of Fe-doped III-V semiconductors were studied by first-principles supercell calculation. It was found that their electronic structures are basically the same as those of Mn-doped ones except that the extra electron of Fe compared to Mn occupies either majority-spin p- d hybridized antibonding states (t a, ↑) or minority-spin e states (e ↓), and that the center of gravity of the d partial density of states is higher for Fe than for Mn. The present calculations suggest that ferromagnetism appears when the e ↓ states start to be occupied. The band splitting due to s- d hybridization was found to be significantly smaller than that due to p- d hybridization. This indicates that the s, p- d exchange interaction is not responsible for the high-temperature ferromagnetism of the Fe-doped ferromagnetic semiconductors even in n-type compounds.