Regensburg 2010 – scientific programme
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MA: Fachverband Magnetismus
MA 33: Poster II
MA 33.11: Poster
Friday, March 26, 2010, 11:00–14:00, Poster B1
Origin of Resonance Structures in Magneto-optical Spectra of InMnSb and InSb — •Christoph Thurn and Vollrath Martin Axt — Theoretische Physik III, Universität Bayreuth, D-95440 Bayreuth, Germany
We have calculated the magneto-optical Kerr and the magnetic circular dichroism spectra of ferromagnetic In0.985Mn0.015Sb and intrinsic InSb using an eight band k→ · p→ model accounting for the coupling to external magnetic fields B = 0.4 … 8 T as well as for the mean-field exchange coupling between holes and Mn spins.
The numerical results show that for InSb the spectra exhibit narrow and distinct resonances which can be associated with dipole-allowed transitions between the Landau levels in conduction and valence bands. With increasing B the Landau and the Zeeman splitting increase, and the observed peaks change their position and amplitude accordingly.
Contrarily, the calculated spectra of the diluted magnetic semiconductor InMnSb show only one strong and broad resonance. The shape and position of this resonance does not change with B. It is found, however, that the amplitude depends linearly on the magnetization M of the samples. Nota bene: B can easily exceed µ0 M. An involved analysis of the band structure and the dipole transitions explains these features. In particular, the spectra of InMnSb are dominated by intra-valence band transitions. Our results are in excellent agreement with measurements performed by A. Winter and H. Pascher.1
1C. Thurn, V. M. Axt, A. Winter, H. Pascher, H. Krenn, X. Liu, J. K. Furdyna, and T. Wojtowicz, Phys. Rev. B 80, 195210 (2009)