Berlin 2005 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 44: II-VI Halbleiter IV

HL 44.4: Vortrag

Montag, 7. März 2005, 15:45–16:00, TU P-N201

Spin flip Raman experiments on heavy doped ZnMnSe diluted magnetic semiconductors — •M. Lentze¹, D. Wolverson², P. Grabs¹, and J. Geurts¹ — ¹Physikalisches Institut der Universität Würzburg, EP III, Am Hubland, D-97074 Würzburg, Germany — ²University of Bath, Dep. of Physics, Bath BA2 7YA, UK

Diluted magnetic semiconductors (DMS) are a promising component for the new spinbased information technology (Spintronics). For spin transport applications, a sufficient doping level is required. For the analysis of the magnetic properties of doped II-VI DMS, we apply spin flip Raman spectroscopy from free electrons under resonant excitation at the fundamental band gap. Our investigations are focused on BeZnMnSe: bulk-like BeZnMnSe epitaxial films with electron concentrations between 10¹⁷ cm⁻³ and 10¹⁹ cm⁻³. Analysis of the Raman signal yields the effective g-factors, the effective Mn-concentration as well as the spin relaxation time. By measurements under different scattering geometry (forward scattering vs. backward scattering) the momentum transfer in the Raman scattering process was varied systematically. In this way we studied the behavior of conduction band electrons in the metal to insolator transition. From our investigations at extremely heavily doped samples we could affirm a model, based on free electrons. The obtained results for the spin relaxation time T₂ and spin diffusion coefficient D_s agree with electrical characterisations and theoretical predictions for these DMS.