Model for the Mn acceptor in GaAs

We present a model based on the Baldereschi-Lipari effective mass theory and the sp-d exchange interaction between the valence band and the Mn d electrons (3d(5)). It fits in with the available experimental data and yields a relationship between the exchange-induced splitting of the 1S(3/2) impurity ground state and the valence band exchange constant N(0)beta. By using the recently reported value of the splitting, deduced from infrared spectroscopy, and fitting the known ground state binding energy, we obtain N(0)beta similar or equal to -0.9 eV. We also study the two-hole bound state in the Hartree self-consistent approximation and account for the absence of Mn-associated bound exciton and discuss the sign anomalies in the magneto-optical data in dilute Ga1-xMnxAs. (C) 1999 Elsevier Science Ltd. All rights reserved.