1303.0258 (C. P. Weber et al.)

Rapid diffusion of electrons in GaMnAs    [PDF]

C. P. Weber, Eric A. Kittlaus, Kassandra B. Mattia, Christopher J. Waight, J. Hagmann, X. Liu, M. Dobrowolska, J. K. Furdyna

We report ultrafast transient-grating measurements, in the paramagnetic state, of the dilute ferromagnetic semiconductor (Ga,Mn)As containing 6% Mn. We observe that photoexcited electrons in the conduction band have a lifetime of 8 ps and diffuse at about 70 cm2/s. Such rapid diffusion requires either an electronic mobility exceeding 7,700 cm2/Vs or a conduction-band effective mass m_e less than half the GaAs value. We further find that m_e cannot greatly exceed the GaAs value, as a large mass would require a long momentum-relaxation time. 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.

View original: http://arxiv.org/abs/1303.0258