Ga1-xMnxAs with Curie temperatures (Tc) as high as 110 K has recently emerged as an important spintronic semiconductor material. The ferromagnetism in this material arises from the exchange interaction between the free carriers (holes) generated by Mn doping and the Mn2+ ions. However, the accurate determination of the carrier concentration in GaGa1-xMnxAs using standard transport techniques is extremely difficult because of the dominant anomalous Hall effect. We have performed spectroscopic measurements of the hole density in four GaGa1-xMnxAs samples (x = 0, 0.038, 0.061, 0.083) using Raman scattering intensity analysis of the coupled plasmon-LO-phonon mode and the unscreened LO phonon. The unscreened LO phonon frequency linearly decreases as the Mn concentration increases up to 8.3 %. The hole density determined from the Raman scattering exhibits a direct correlation to the observed Tc, providing an unambiguous means of determining the hole density in this important new class of ferromagnetic semiconductors.
|Journal of the Korean Physical Society
|Published - Feb 1 2003
|Proceedings of The 11th Seoul International Symposium on the Physics of Semiconductors and Apllications - 2002 - Cheju Island, Korea, Republic of
Duration: Aug 20 2002 → Aug 23 2002
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy