Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 51: Poster IV

HL 51.51: Poster

Donnerstag, 28. Februar 2008, 16:30–19:00, Poster D

Magneto-optic photoluminescence and spin flip Raman spectroscopy on Cd_1−xMn_xTe/Cd_1−yMg_yTe quantum well samples — •Christian Kehl, Georgy Astakhov, Jean Geurts, and Wolfgang Ossau — Universität Würzburg, Physikalisches Institut, Experimentelle Physik III, Am Hubland, 97074 Würzburg

Using magneto-optic photoluminescence and spin flip Raman spectroscopy up to 4.5 tesla at 1.7 Kelvin, Cd_1−xMn_xTe quantum wells (QW) embedded in Cd_1−yMg_xTe barriers were investigated. The PL spectra show excitonic and trionic excitations of the quantum well. For the Raman study of paramagnetic resonance spin flips of Mn-ions resonant excitation of excitons in the QW was applied. In this way, multiple spin flips up to the fourth order were observed. We studied the effect of additional carriers in the QW both by increasing the illumination intensity at the excitonic level and by additional illumination beyond the barrier gap.

The results are discussed in terms of (i) the increase of trion intensity at the expense of the excitons, (ii) the influence of the photogenerated carriers on the multiple spin flip intensities and on the Mn g-factor. Thus, we gain insight into the effect of additional free carriers on the Mn-Mn-exchange interaction.