Dresden 2006 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

HL: Halbleiterphysik

HL 9: Poster I

HL 9.37: Poster

Monday, March 27, 2006, 15:15–17:45, P3

Influence of confinement effects and carrier concentration on spin relaxation rates studied by spin-flip Raman spectroscopy on heavily doped (Zn,Mn)Se and (Cd,Mn)Te — •M. Lentze¹, L. C. Smith², D. Wolverson², P. Grabs¹, and J. Geurts¹ — ¹Universität Würzburg, Experimentelle Physik III, Am Hubland, 97074 Würzburg — ²University of Bath, Department of Physics, Bath BA2 7AY, United Kingdom

Spin-flip Raman spectroscopy (SFRS) is a convenient way to study optical properties of diluted magnetic semiconductors (DMS). Especially useful features of the technique are optical material selectivity (important for heterostructures) as well as high sensitivity. We studied II-VI semiconductors like Zn_(1−x)Mn_xSe and Cd_(1−x)Mn_xTe which are promising components for the new spin based information technology (spintronics).

Our investigations are focused on n-doped heterostructures, containing quantum wells with 2DEG ((Zn,Mn)Se and (Cd,Mn)Te) embedded in (Zn,Be)Se and (Cd,Mg)Te respectively. Analysing the Raman signal we obtain the effective Manganese content, the g-values of the electrons and their exchange parameter N₀α. A non-ambiguous influence of confinement and electron concentration in the quantum wells on the SFRS linewidth occurs for both material systems.

Besides backward scattering experiments, also spin-flip Raman spectra in forward scattering were taken, after selective substrate etching. By the comparison of half width of the SFRS signals we could determine spin relaxation times T₂ as well as spin diffusion constants D_s. An obvious decrease of T₂ with increasing n-doping level could be demonstrated.