Berlin 2005 – scientific programme

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HL: Halbleiterphysik

HL 21: Spintronik III

HL 21.2: Talk

Saturday, March 5, 2005, 11:00–11:15, TU P164

Strain-induced spin splitting determined from B=0 spin precession, and spin lifetimes of drifting electrons in n-GaAs — •Markus Beck, Claus Metzner, Stefan Malzer und Gottfried H. Döhler — Institut für Technische Physik I, Universität Erlangen-Nürnberg, Erwin-Rommel-Str. 1, D-91058 Erlangen

In stationary Faraday rotation measurements, we observe the spin transport of photoexcited electrons in n-GaAs spatially resolved. The measured spatial distribution of spin polarization under transport conditions allows for the determination of spin lifetimes and their dependencies on the applied field, temperature and doping density. Externally applied strain results in a k-linear spin splitting, which causes spin precession on a length scale inversely proportional to the applied strain, independent of the electron drift velocity. Successively increasing the sample strain along [110] allows to determine the strain-induced spin splitting along [110] quantitatively. In accordance with the theoretical expectation, we observe no spin splitting along [100] for strain along [100]. We present the measured results together with calculations of the spin transport, which quantitatively explain the observed decrease of the spin lifetime with the applied field in terms of an increased electron temperature.