Observation of insulating nanoislands in ferromagnetic GaMnAs

Wang, D. M.; Ren, Y. H.; Jacobs, P. W.; Fahy, Stephen B.; Liu, X.; Furdyna, J. K.; Sapega, V. F.; Merlin, Roberto

Observation of insulating nanoislands in ferromagnetic GaMnAs

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Published Version

Date

2009

Authors

Wang, D. M.

Ren, Y. H.

Jacobs, P. W.

Fahy, Stephen B.

Liu, X.

Furdyna, J. K.

Sapega, V. F.

Merlin, Roberto

Publisher

American Physical Society

Published Version

10.1103/PhysRevLett.102.256401

Abstract

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.

Keywords

Electronic structure , Bulk gaAs , Mn , Ga1-xMnxAs , Semiconductors , Spectroscopy , Temperature , Acceptor , Raman

Citation

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