title: Observation of insulating nanoislands in ferromagnetic GaMnAs.
abstract: Resonant Raman data on ferromagnetic GaMnAs reveal the existence of a new kind of defect: insulating nanoislands consisting of substitutional MnGa acceptors surrounded by interstitial MnI donors. As indicated by the observation of a sharp 1S3/2-->2S3/2 Raman transition at approximately 703 cm(-1), the acceptor-bound holes inside the islands are isolated from the metallic surroundings. Instead, Mn-bound excitons do couple to the ferromagnetic environment, as shown by the presence of associated Raman magnon side bands. This leads to an estimate of 5-10 nm for the nanoisland radius. The islands disappear after annealing due to the removal of the MnI ions.
authors: Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040, USA.
authors: D M
authors: DM
authors: Wang
authors: Y H
authors: YH
authors: Ren
authors: P W
authors: PW
authors: Jacobs
authors: S
authors: S
authors: Fahy
authors: X
authors: X
authors: Liu
authors: J K
authors: JK
authors: Furdyna
authors: V F
authors: VF
authors: Sapega
authors: R
authors: R
authors: Merlin