Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 30: ZnO and Relatives I
HL 30.3: Talk
Tuesday, March 27, 2012, 10:00–10:15, EW 202
Spin noise spectroscopy on ZnO — •Hauke Horn1, Andrea Balocchi2, Xavier Marie2, Andrey Bakin3, Andreas Waag3, Jens Hübner1, and Michael Oestreich1 — 1Institute for Solid State Physics, Leibniz University Hannover, Appelstr. 2, 30167 Hannover, Germany — 2INSA-CNRS-UPS, LPCNO, Université de Toulouse, 135 Av. de Rangueil, 31077 Toulouse, France — 3Institut für Halbleitertechnik, Technische Universität Braunschweig, Hans-Sommer-Straße 66, 38106 Braunschweig, Germany
We measure the fluctuating magnetization noise of an ensemble of localized donor electrons in ZnO with high sensitivity spin noise spectroscopy. The measurement technique allows us to probe the equilibrium spin dynamics of our sample by nearly dissipation free, below band gap Faraday rotation. In our measurements an additional magnetic field applied in Voigt geometry modulates the spin noise signal with the Larmor frequency ωL=g* µB B /ℏ where g* is the electron g–factor, µB the Bohr magneton and B the magnetic field.
We probe the Faraday rotation noise of the equilibrium donor electron spins. The T2* time is shortened to 20 ns due to the inhomogeneous hyperfine interaction. This HF interaction becomes negligible when a longitudinal magnetic field is applied and hence the T1 (and T2) time becomes measurable. We further investigate the effects of laser light excitation on the spin dynamics of free electrons and reveal clear differences between intrinsic spin lifetime measurements and excitation effects.