title: Self-compensation in manganese-doped ferromagnetic semiconductors.
abstract: We present a theory of interstitial Mn in Mn-doped ferromagnetic semiconductors. Using density-functional theory, we show that under the nonequilibrium conditions of growth, interstitial Mn is easily formed near the surface by a simple low-energy adsorption pathway. In GaAs, isolated interstitial Mn is an electron donor, each compensating two substitutional Mn acceptors. Within an impurity-band model, partial compensation promotes ferromagnetic order below the metal-insulator transition, with the highest Curie temperature occurring for 0.5 holes per substitutional Mn.
authors.affiliation: Center for Computational Materials Science, Naval Research Laboratory, Washington, DC 20375, USA.
authors.forename: Steven C
authors.initials: SC
authors.lastname: Erwin
authors.forename: A G
authors.initials: AG
authors.lastname: Petukhov