Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 27: Zinc Oxide and Zinc Selenide

HL 27.11: Vortrag

Dienstag, 8. März 2016, 12:30–12:45, H17

ODNMR studies of selenium nuclei in a flourine-doped ZnSe epilayer — •Erik Kirstein¹, Fabian Heisterkamp¹, Alexander Greilich¹, Evgeny A. Zhukov¹, Tomasz Kazimerczuk¹, Dmitri R. Yakovlev^1,2, Alexander Pawlis³, and Manfred Bayer¹ — ¹Experimentelle Physik 2, Technische Universität Dortmund, 44221 Dortmund, Germany — ²Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia — ³Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany

A longitudinal (T₁) and transverse (T₂) relaxation times of selenium nuclei present in a fluorine-doped ZnSe epilayer are studied by optically detected nuclear magnetic resonance. Circularly polarized laser pulses optically orient the electron spins, which in its turn polarize the nuclei. The nuclear polarization of selenium reveals itself as an Overhauser field, affecting, in its turn, the electron Larmor frequency in tranverse magnetic field, measured by Kerr rotation [1]. The changes of the Larmor frequency are then analized in timescale to measure: the time needed for a complete polarization of the nulcear system under the optical excitation (T_pol), and the time needed for a system to come back to equilibrium in a complete darkness, T₁. Furthermore, radio frequency pulses are applied to measure the inhomogeneous T₂^* and homogeneous T₂ nuclear spin coherence using Ramsey and Hahn-Echo pulse sequences. Finally, we found that the spin temperature approach is fully justified for that system, as T₁ ≫ T₂. [1] F. Heisterkamp, et al., arXiv:1508.05295 [cond-mat.mes-hall]