All-electrical time-resolved spin generation and coherent spin manipulation in n-InGaAs

Creation and manipulation of coherent spin information by electrical means are key tasks in semiconductor spintronics. Here we demonstrate that a coherent spin polarization can be created and manipulated by two successive electric field pulses in n-InGaAs epilayer at zero external magnetic field. The first electric pulse vertical stroke vertical stroke [1 anti 10] creates a current induced spin polarization (CISP) which is oriented in the plane of the sample. The subsequent electric field pulse vertical stroke vertical stroke [110] generates a perpendicular magnetic field pulse leading to a coherent precession of this spin polarization with 2-dimensional electrical control over the final spin orientation. Spin precession is measured by time-resolved Faraday rotation. We determine the build-up time of CISP during the first field pulse and extract the spin dephasing time and internal magnetic field strength during the spin manipulation pulse. The results are in good agreement with optical pump-probe experiments on the same device.