We report ultrafast transient-grating measurements, above and below the Curie
temperature, of the dilute ferromagnetic semiconductor (Ga,Mn)As containing 6%
Mn. At 80 K (15 K), we observe that photoexcited electrons in the conduction
band have a lifetime of 8 ps (5 ps) and diffuse at about 70 cm2/s (60 cm2/s).
Such rapid diffusion requires either an electronic mobility exceeding 7,700
cm2/Vs or a conduction-band effective mass less than half the GaAs value. Our
data suggest that neither the scattering rate nor the effective mass of the
(Ga,Mn)As conduction band differs significantly from that of GaAs.Comment: 5 pages, 3 figures. Differs from the previous version in
incorporating additional data and changes made during the review process.
Differs from the published version in including section headings and in
omitting AIP copy-edits. No substantial differences in scientific conclusions
from either versio