Infrared optical conductivity of In1−xMnxAs

We have investigated the infrared optical absorption coefficient α(ω) of p-type diluted magnetic semiconductor In1−xMnxAs in the photon energy range up to View the MathML source. α(ω) exhibits a quasi-Drude as well as interband transition components. It has been found that the quasi-Drude component of α(ω) increases with decreasing temperature, T, whereas the interband component decreases. Such a temperature dependent shift in the spectral weight strongly suggests that, in addition to the p–d exchange interaction, the double-exchange-like mechanism is participating in the ferromagnetic ordering process in III–V diluted magnetic semiconductors. From the far infrared data, it is concluded that the hopping range of the conducting holes is of the order of inter-Mn ion distance.