Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 48: Focus Session: Spintronics (jointly with MA)

HL 48.11: Vortrag

Mittwoch, 28. März 2012, 12:45–13:00, EW 201

Hot carrier effects on lateral electron spin diffusion in n-type GaAs — •Tobias Henn, Jan-Henrik Quast, Tobias Kiessling, and Wolfgang Ossau — Physikalisches Institut (EP3) der Universität Würzburg, 97074 Würzburg, Germany

We report on spatially resolved two-color Hanle-MOKE studies of low temperature electron spin diffusion in bulk n-type GaAs. We investigate the influence of lattice temperature and external magnetic fields on the lateral electron spin diffusion for a broad range of donor concentrations covering the insulating and metallic regime.

Our results demonstrate that the commonly used standard drift-diffusion model [1,2] is not capable of describing the lateral spin diffusion profiles observed under non-resonant optical spin injection. We find that the non-resonant optical excitation results in a local heating of the electron system with respect to the lattice which persists over length scales comparable to the spin diffusion length. Consideration of this hot carrier effect is demonstrated to be crucial for reliable extraction of spin propagation parameters from optical experiments.

[1] S. A. Crooker and D. L. Smith, PRL, 94 (2005), 236601

[2] M. Furis et al., NJP, 9 (2007), 347