Ground-state properties and the molecular theory of the Curie temperature in the coherent potential approximation of diluted magnetic semiconductors

Using a spin-1/2 description of valence holes and Kondo coupling between local spins and carriers, GaAs-based III-V diluted magnetic semiconductors (DMS) are studied in the coherent potential approximation (CPA). Our calculated relation between ground-state energy and impurity magnetization shows that ferromagnetism is always favourable at low temperatures. For very weak Kondo coupling, the density of states (DOS) of the host semiconductor is not modified much. Impurity bands can be generated at the bottom of the host band only when Kondo coupling is strong enough. Using Weiss molecular theory, we predict a linear relation of Curie temperature with respect to Kondo coupling and doping concentration x if the hole density is proportional to x