Two-Dimensional Optical Control of Electron Spin Orientation by Linearly Polarized Light in InGaAs

II. Institute of Physics, RWTH Aachen University, Otto-Blumenthal-Straße, 52074 Aachen, Germany.
Physical Review Letters (Impact Factor: 7.51). 12/2010; 105(24):246603. DOI: 10.1103/PhysRevLett.105.246603
Source: PubMed


Optical absorption of circularly polarized light is well known to yield an electron spin polarization in direct band gap semiconductors. We demonstrate that electron spins can even be generated with high efficiency by absorption of linearly polarized light in InxGa(1-x)As. By changing the incident linear polarization direction we can selectively excite spins in both polar and transverse directions. These directions can be identified by the phase during spin precession using time-resolved Faraday rotation. We show that the spin orientations do not depend on the crystal axes suggesting an extrinsic excitation mechanism.

Download full-text


Available from: Klaus Schmalbuch, May 27, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Time-resolved electrical spin transport is used to generate and probe spin currents in GaAs electrically. We use high bandwidth current pulses to inject phase-coherent spin packets from Fe into n-GaAs. By means of time-resolved Faraday rotation we demonstrate that spins are injected with a clearly defined phase by the observation of multiple Larmor precession cycles. We furthermore show that spin precession of optically created spin packets in n-GaAs can be probed electrically by spin-polarized photo-current pulses. The injection and detection experiments are not direct reciprocals of each other. In particular, we find that interfacial spin accumulation generated by the photocurrent pulse plays a critical role in time-resolved electrical spin detection.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Full electric-field control of spin orientations is one of the key tasks in semiconductor spintronics. We demonstrate that electric-field pulses can be utilized for phase-coherent ±π spin rotation of optically generated electron spin packets in InGaAs epilayers detected by time-resolved Faraday rotation. Through spin-orbit interaction, the electric-field pulses act as local magnetic field pulses. By the temporal control of the local magnetic field pulses, we can turn on and off electron spin precession and thereby rotate the spin direction into arbitrary orientations in a two-dimensional plane. Furthermore, we demonstrate a spin-echo-type spin drift experiment and find an unexpected partial spin rephasing, which is evident by a doubling of the spin dephasing time.
    Physical Review Letters 10/2012; 109(14):146603. DOI:10.1103/PhysRevLett.109.146603 · 7.51 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The experimental demonstration of the spin Hall effect in a high mobility two-dimensional electron system is reported. The spatial dependence is studied by Kerr rotation as a function of the external magnetic field using an applied electric field amplitude and direction as control parameters. We observe that the effect is robust in a bilayer structure with a nonzero Rashba coefficient displayed by an electrically controllable internal magnetic field, a large spin Hall conductivity in the range of the universal intrinsic value, and a mobility-enhanced spin diffusion constant. With the application of an unidirectional electric field, the role of the spin drift was also studied. The data was analyzed following both phenomenological and microscopic approaches and compared with experimental references in a single-layer configuration.
    Physical Review B 10/2013; 88(16). DOI:10.1103/PhysRevB.88.161305 · 3.74 Impact Factor
Show more