Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 10: Spinelectronics/Spininjection in Heterostructures
MA 10.12: Vortrag
Montag, 26. März 2007, 18:00–18:15, H23
Proof of coherent electrical spin injection across a Fe/GaAs interface — •Lars Schreiber1, Sebastian Schulz1, Bernd Beschoten1, Gernot Güntherodt1, Christoph Adelmann2, Paul Crowell2, and Chris Palmstrøm2 — 12. Physikalisches Institut, Aachen University, Germany and Virtual Institute for Spinelectronics — 2University of Minnesota, Minneapolis, USA
Electrical spin injection from a ferromagnet into a semiconductor was shown for different material systems [1,2] and recently even high injection efficiency for electron spins has been achieved [3]. Despite this progress, an essential ingredient for spintronics is still missing: electrical injection of coherent spin packets. In all-optical time-resolved measurements, coherent spins can be readily oriented using 100 fs circularly polarised laser pulses and probed by means of time-resolved Faraday rotation (TRFR) [4]. However, no time-resolved measurement of electrical spin injection has been successfully performed yet.
Therefore, we apply ns-current pulses in order to electrically inject short spin packets from a Fe injector through a reverse biased Schottky barrier into 5 µm thick bulk n-GaAs, which exhibits long spin relaxation time. Probing the injected spins in the GaAs layer with TRFR, we observe spin precession and resonant spin amplification [4] in a transverse magnetic field. This proofs the phase-coherence of the electrical injected spin packet. The result will be compared to all-optical TRFR measurements. Supported by BMBF FKZ 13N8244 and HGF.
[1] Y. Ohno, Nature 402 (1999) [2] H. J. Zhu, PRL 87 (2001)
[3] C. Adelmann, PRB 71 (2005) [4] J. M. Kikkawa, PRL 80 (1998)