Observation of insulating nanoislands in ferromagnetic GaMnAs
Wang, D. M.
Ren, Y. H.
Jacobs, P. W.
Fahy, Stephen B.
Furdyna, J. K.
Sapega, V. F.
American Physical Society
Resonant Raman data on ferromagnetic GaMnAs reveal the existence of a new kind of defect: insulating nanoislands consisting of substitutional Mn-Ga acceptors surrounded by interstitial Mn-I donors. As indicated by the observation of a sharp 1S(3/2)-> 2S(3/2) Raman transition at similar to 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 Mn-I ions.
Electronic structure , Bulk gaAs , Mn , Ga1-xMnxAs , Semiconductors , Spectroscopy , Temperature , Acceptor , Raman
Wang, D. M., Ren, Y. H., Jacobs, P. W., Fahy, S., Liu, X., Furdyna, J. K., Sapega, V. F. and Merlin, R. (2009) 'Observation of insulating nanoislands in ferromagnetic GaMnAs', Physical Review Letters, 102(25), 256401 (4pp). doi: 10.1103/PhysRevLett.102.256401
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