Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 32: Poster I: Group II - Oxides
HL 32.6: Poster
Tuesday, March 23, 2010, 18:30–20:30, Poster D1
Spin Noise Spectroscopy of ZnO — •Hauke Horn1, Xavier Marie2, Andrea Balocchi2, Jens Hübner1, and Michael Oestreich1 — 1Institute for Solid State Physics, Gottfried Wilhelm Leibniz University Hannover, Appelstr. 2, 30167 Hannover, Germany — 2INSA-CNRS-UPS, LPCNO, Université de Toulouse, 135 Av. de Rangueil, 31077 Toulouse, France
ZnO is a promising material for optical spintronics showing long electron spin lifetimes due to the large band gap and low amount of nuclear spin isotopes. Here, we use spin noise spectroscopy to access the electron spin dynamics of this material in thermal equilibrium while avoiding carrier heating and excitation of electron hole pairs.
A linear polarized laser beam (EUV−Laser=3.32 eV) close to the direct band gap of ZnO (ED0X = 3.36 eV) is used to detect the spin dynamics of neutral donors in ZnO with off–resonant, non–demolition Faraday rotation. The stochastic oriented electron spins induce polarization fluctuations of the transmitted laser beam. The fluctuation strength of N non–interacting, paramagnetic spins follow the Poisson statistics and generate measurable noise ∝ √N spins. These fluctuations are measured via a polarization bridge in the radio frequency regime and Fourier transformed in real–time. A magnetic field B is applied in Voigt–geometry and modulates the noise signal with the Larmor frequency of the electron spins ωL=gµB B/ℏ. From the recorded noise spectra we can extract the electron g–factor, spin lifetimes, and densities.