Electronic structure of Mn ions in (Ga,Mn)As diluted magnetic semiconductor

The electronic structure of Mn in the diluted magnetic semiconductor (Ga,Mn)As was studied by means of electronic and spin-flip Raman scattering. The Mn ion was found to manifest itself in three different electronic configurations: (i) neutral Mn acceptor, i.e., Mn ${3d}^5$ inner-shell electrons with a weakly bound valence band hole, (ii) ionized Mn acceptor, i.e., ${3d}^5$ state, and (iii) neutral Mn in the ${3d}^4$ electronic configuration. The latter state undergoes a crystal-field splitting and a Jahn-Teller effect. The energy separation between the optical dipole active sublevels of the ${}^5{T}_2$ ground state is directly measured in the dynamic Jahn-Teller-effect regime. The Mn ${3d}^4$ state is assumed to play an important role for the ferromagnetism observed in diluted (Ga,Mn)As.