Triggering phase-coherent spin packets by pulsed electrical spin injection across an Fe/GaAs Schottky barrier

Physical review. B./Physical review. B, vol. 104

Abstract

The precise control of spins in semiconductor spintronic devices requires electrical means to generate spin packets with a well-defined initial phase. We demonstrate a pulsed electrical scheme that triggers the spin ensemble phase in a similar way as circularly polarized optical pulses generate phase coherent spin packets. Here, we use fast current pulses to initialize phase coherent spin packets, which are injected across an Fe/GaAs Schottky barrier into $n$-GaAs. By means of time-resolved Faraday rotation, we demonstrate phase coherence by the observation of multiple Larmor precession cycles for current pulse widths down to 500 ps at 17 K. We show that the current pulses are broadened by the charging and discharging time of the Schottky barrier. At high frequencies, the observable spin coherence is limited only by the finite bandwidth of the current pulses, which is of the order of 2 GHz. These results therefore demonstrate that all-electrical injection and phase control of electron spin packets at microwave frequencies is possible in metallic-ferromagnet--semiconductor heterostructures.

Authors 9

1. Lars R. Schreiber Aachen 2nd Institute of Physics and JARA-FIT JARA-FIT Institute for Quantum Information

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   2nd Institute of Physics and JARA-FIT, RWTH Aachen University, 52074 Aachen, Germany

   JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, 52074 Aachen, Germany

2. Christoph Schwark Aachen 2nd Institute of Physics and JARA-FIT

   RWTH Aachen University

   Affiliation as printed

   2nd Institute of Physics and JARA-FIT, RWTH Aachen University, 52074 Aachen, Germany

3. Gernot Guntherodt Aachen 2nd Institute of Physics and JARA-FIT

   RWTH Aachen University

   Affiliation as printed

   2nd Institute of Physics and JARA-FIT, RWTH Aachen University, 52074 Aachen, Germany

4. Mihail Ion Lepsa

   Forschungszentrum Jülich

   Affiliation as printed

   Peter Grünberg Institute (PGI-10), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

5. Christoph Adelmann

   University of Minnesota · IMEC

   Affiliation as printed

   Department of Chemical Engineering and Material Science, University of Minnesota, Minneapolis, Minnesota 55455, USA

   IMEC, 3001 Leuven, Belgium

6. C. J. Palmstrøm

   University of Minnesota · University of California, Santa Barbara

   Affiliation as printed

   Department of Chemical Engineering and Material Science, University of Minnesota, Minneapolis, Minnesota 55455, USA

   Departments of Electrical and Computer Engineering and Materials, University of California, Santa Barbara, California 93106, USA

7. Xiaohua Lou

   University of Minnesota

   Affiliation as printed

   School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA

8. P. A. Crowell

   University of Minnesota

   Affiliation as printed

   School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA

9. Bernd Beschoten Aachen 2nd Institute of Physics and JARA-FIT

   RWTH Aachen University

   Affiliation as printed

   2nd Institute of Physics and JARA-FIT, RWTH Aachen University, 52074 Aachen, Germany