Abstract
We report infrared studies of the insulator-to-metal transition (IMT) in GaAs doped with either magnetic (Mn) or nonmagnetic acceptors (Be). We observe a resonance with a natural assignment to impurity states in the insulating regime of GaMnAs, which persists across the IMT to the highest doping (16%). Beyond the IMT boundary, behavior combining insulating and metallic trends also persists to the highest Mn doping. Be-doped samples, however, display conventional metallicity just above the critical IMT concentration, with features indicative of transport within the host valence band.
- Received 18 July 2011
DOI:https://doi.org/10.1103/PhysRevB.84.081203
©2011 American Physical Society