Microscopic mechanism of high-temperature ferromagnetism in Fe, Mn, and Cr-doped InSb, InAs, and GaSb magnetic semiconductors
Jing‐Yang You, Bo Gu, Sadamichi Maekawa, Gang Su
Abstract
In recent experiments, high Curie temperatures ${T}_{c}$ above room temperature were reported in ferromagnetic semiconductors Fe-doped GaSb and InSb, while low ${T}_{c}$ between 20 K to 90 K were observed in some other semiconductors with the same crystal structure, including Fe-doped InAs and Mn-doped GaSb, InSb, and InAs. Here we study systematically the origin of high temperature ferromagnetism in Fe, Mn, Cr-doped GaSb, InSb, and InAs magnetic semiconductors by combining the methods of density functional theory and quantum Monte Carlo. In the diluted impurity limit, the calculations show that the impurities Fe, Mn, and Cr have similar magnetic correlations in the same semiconductors. Our results suggest that high (low) ${T}_{c}$ obtained in these experiments mainly comes from high (low) impurity concentrations. In addition, our calculations predict the ferromagnetic semiconductors of Cr-doped InSb, InAs, and GaSb that may have possibly high ${T}_{c}$. Our results show that the origin of high ${T}_{c}$ in (Ga,Fe)Sb and (In,Fe)Sb is not due to the carrier induced mechanism because ${\mathrm{Fe}}^{3+}$ does not introduce carriers.