First-principles investigation of the magnetic transition in Fe-doped GaSb and InSb

Recently, Fe-doped semiconductors have been attracting much attention as ferromagnetic semiconductors due to the possibility of high Curie, fascinating functions such as low power consumption and high-speed operation, and fabrication of both n- and p-type. In this study, we have focused on GaSb and InSb as host semiconductors, and performed density functional theory calculations using the Korringa-Kohn-Rostoker Green’s function method with the coherent potential approximation (KKR-CPA). Our calculations reveal that, (Ga,Fe)Sb and (In,Fe)Sb show complex magnetic properties, which are determined by the correlation between magnetic exchange coupling constants and chemical pair interactions. Isoelectronic Fe-doped GaSb and InSb show strong antiferromagnetic interactions that originate from the super-exchange mechanism works between the Fe atoms. By modulating the chemical potentials–i.e., by n- or p-type doping–, the magnetic property can be changed drastically from antiferromagnetism to ferromagnetism, because the ferromagnetic double exchange mechanism becomes dominant. This transition can be well understood in terms of the Alexander-Anderson-Moriya mechanism. Our calculations indicate the possibility of manipulating (Ga,Fe)Sb and (In,Fe)Sb to achieve high Curie temperatures.