Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 21: Poster IB (Oxide semiconductors; II-VI and group IV semiconductors; Nanotubes and Buckyballs)

HL 21.26: Poster

Montag, 16. März 2015, 15:00–20:00, Poster B

Determination of the Mn-spin temperature of photo-excited n-doped Zn_1−xMn_xSe by magneto-luminescence and spin-flip Raman spectroscopy — •Alexander Gerhard Knapp¹, Michael Hetterich², and Jean Geurts¹ — ¹Universität Würzburg, Experimentelle Physik 3, Würzburg, Germany — ²Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

The wide-gap semiconductor Zn_1−xMn_xSe, as a II-VI-based diluted magnetic semiconductor, offers the opportunity for an independent tuning of the magnetic and the electronic properties by variation of either the Mn content or the dopant concentration. The strong s,p-d exchange coupling gives rise to a giant Zeeman splitting in magneto-photoluminescence (PL). Furthermore, magneto-Raman spectroscopy (RS) shows local spin flip excitations on Mn atoms, as well as electronic spin flip excitations of donator atoms in n-type material. The spectral position of the latter reflects the spin-selective energy splitting of the conduction band due to the s-d exchange interaction. We performed polarization-selective magneto-PL and and magneto-RS on Zn_1−xMn_xSe (x = .05 to .06) with various n-doping levels up to 10¹⁸ cm⁻³, i.e. up to the range of the Mott density, at T = 1.6 K in Voigt configuration in B-fields up to 7 T. For near-resonant optical excitation in the range of the fundamental energy gap E₀, we investigated the influence of the variation of excitation power on the Mn-spin temperature. For this purpose, the Brillouin-function fit parameters of the PL- and RS-peak positions as well as the Stokes-to-Anti-Stokes intensity ratio of the local Mn spin flip were evaluated.