Ferromagnetism and Its Stability in the Diluted Magnetic Semiconductor (In, Mn)As

Carrier-induced ferromagnetism in the doped diluted magnetic semiconductors $(\mathrm{In},\mathrm{Mn}\uparrow ,\mathrm{Mn}\downarrow ,A)\mathrm{As}$, where $A$ is As or Sn and $\mathrm{Mn}\uparrow$ ( $\mathrm{Mn}\downarrow$) denotes Mn atoms whose local magnetic moment is parallel (antiparallel) to the magnetization, are investigated using the Korringa-Kohn-Rostoker coherent-potential approximation and local density approximation first-principles calculation. The result shows that (i) the ferromagnetic state is stable due to the double exchange at low concentrations of $A$, and (ii) a spin-glass-like local-moment disordered state, which stems from the superexchange, is more favorable when the Mn $d$ holes are nearly compensated.