What Limits Magnetic Polaron Energies in DMS?

Abstract

Magnetic polarons are ferromagnetic spin clusters created by the exchange interaction of a carrier spin (electron or hole) with localized spins imbedded in a semiconductor lattice. They were first studied in magnetic semiconductors [1]; more recently, there have been extensive investigations [2] of polaron behavior in diluted magnetic semiconductors (DMS), such as Cd1−xMnxTe. DMS are favorable media for magnetic polaron studies because they have simple s-p bands and excellent optical properties. Two types of magnetic polarons have been identified in DMS - the bound magnetic polaron (BMP), whose carrier is localized by an impurity [3], and the free polaron (FP) consisting of a carrier trapped by its own, self-consistently-maintained, exchange potential [4].