Magnetic polaron associated with a hole in zinc-blende semimagnetic semiconductors

Abstract

A theory of hole magnetic polarons in diluted magnetic semiconductors of zinc-blende structure is presented, following the method introduced by Baldereschi and Lipari to solve the neutral acceptor problem. An expression for the nonlinear magnetic potential is determined in the mean-field approximation. An efficient numerical procedure is used to solve the system of coupled differential equations. Through a careful examination of the two magnetization limits, saturation and linear, we show why simplified models based on a single parabolic band are inadequate. Results are presented first for neutral acceptor bound magnetic polarons in CdMnTe, where an excellent parameter-free fit of the polaron energy versus temperature is obtained for diluted systems. Finally, we treat the case of the exciton magnetic polaron in spherical quantum dots, obtaining a good agreement with experiments in CdMnSe nanocrystals.