Double-exchange-like interaction in Ga1-xMnxAs investigated by infrared absorption spectroscopy -: art. no. 193312

We have investigated the infrared optical absorption alpha(omega) of ferromagnetic p-type Ga1-xMnxAs. The observed alpha(omega) showed very non-Drude characteristics, indicating that the holes are nearly localized by disorder. Furthermore, a temperature-dependent spectral transfer between interband and intraband transitions is observed, which strongly suggests that the double-exchange-like mechanism is playing an important role in the ferromagnetic ordering process in III-V diluted magnetic semiconductors. The origin of resistance kinks near T-c (often attributed to critical scattering) is also discussed.