Dresden 2006 – scientific programme
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HL: Halbleiterphysik
HL 21: Transport properties I
HL 21.4: Talk
Tuesday, March 28, 2006, 17:15–17:30, BEY 118
Quantitative modelling of the temperature and magnetic-field dependence of the resistivity of paramagnetic Ga1−xMnxAs with x up 7% — •C. Michel1, S. Ye1, V. Rajevac1, P.J. Klar1, S.D. Baranovskii1, P. Thomas1, W. Heimbrodt1, and B. Goldlücke2 — 1Dept. Physics and WZMW, Philipps-University of Marburg, Germany — 2MPI for Computer Science, Saarbrücken, Germany
We measured and modelled quantitatively the magneto-resistance behaviour above the Curie-temperature of several different p-type Ga1−xMnxAs samples with x up to 7%. A network model [1] accounting for alloy disorder and tuning of the band structure due to the strong s,p-d exchange interaction between the spins of the extended band states and the localized Mn 3d spins was employed. The band structure description is based on parabolic hole bands and an acceptor level with a Gaussian broadening. The calculated temperature dependence of the resistance in zero-field as well as the magnitude of the magneto-resistance effects are very sensitive to the choice of model parameters, e.g. the valence band exchange-integral N0β, the width of the Gaussian broadening of the acceptor level, the degree of zero-field disorder etc., allowing one to determine these parameters by fitting the experimental data. The magnitude of the extracted parameters and the trends with x will be discussed and compared with literature values.
[1] Phys. Rev. B 69, 165211 (2004).