Impurity Band Conduction in a High Temperature Ferromagnetic Semiconductor

K. S. Burch, D. B. Shrekenhamer, E. J. Singley, J. Stephens, B. L. Sheu, R. K. Kawakami, P. Schiffer, N. Samarth, D. D. Awschalom, D. N. Basov.
Impurity Band Conduction in a High Temperature Ferromagnetic Semiconductor
Phys. Rev. Lett. 97, 087208 (2006)