Semiconductor Physics, Quantum Electronics & Optoelectronics. 2008. V. 11, N 3. P. 257-265.
https://doi.org/10.15407/spqeo11.03.257

Thermoelectric studies of electronic properties of ferromagnetic GaMnAs layers
V. Osinniy1, K. Dybko1, A. Jedrzejczak1, M. Arciszewska1, W. Dobrowolski1, and T. Story1, M.V. Radchenko2, V.I. chkovskiy2, and G.V. Lashkarev2, S.M. Olsthoorn3, J. Sadowski4

1Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
2Institute for Problems of Materials Science, National Ukrainian Academy of Sciences 3, Krzhizhanovskogo str., 03180 Kyiv, Ukraine, e-mail: radch@isp.kiev.ua
3Research Institute for Materials, High Magnetic Field Laboratory, University of Nijmegen, Toemooiveld 1, 6525 ED Nijmegen, The Netherlands
4Max-lab, Lund University, SE-221 00 Lund, Sweden

Abstract. Thermoelectric power, electrical conductivity, and high field Hall effect were studied over a broad temperature range in ferromagnetic Ga 1-x Mn x As epitaxial layers (0.015 ≤ x ≤ 0.06). Thermoelectric power analysis gives information about carrier transport mechanisms in layers with both metallic and non-metallic types of conductivity and allows determination of the Fermi energy and carrier concentration. At high temperatures (T > 70 K), the thermoelectric power in GaMnAs linearly increases with increasing temperature. That indicates the presence of a degenerate hole gas with the Fermi energy E F = 220 ± 25 meV, nearly independent of Mn content (for 0.02 ≤ x ≤ 0.05). At lower temperatures, GaMnAs layers with metallic-type conductivity show an additional contribution to the thermoelectric power with the maximum close to the Curie temperature.

Keywords: thermoelectric power, ferromagnetic Ga 1-x Mn x As, Curie temperature.

Full Text (PDF)

Back to N3 Volume 11