Several types of spin-based logic devices have been proposed in recent years. Almost all of them are operated by employing the drift transport of electron spins under in-plane electric fields. However, it is still unclear how an in-plane electric field influences the spin dynamics of drifting electrons. Here, we demonstrated long-distance spin transport in a GaAs quantum well, where the spin-orbit interactions (SOI) were set at exactly the SU(2) symmetry generating a persistent spin helix (PSH) state. The spatial distribution and temporal development of optically-injected electron spins in a modulation-doped GaAs single quantum well were detected with Kerr rotation microscopy based on the pump-probe technique at T = 8 K. We found that the transport length of drifting spins in a PSH condition exceeds 100 micrometers due to the suppression of D’yakonov-Perel spin relaxations . The spin precession period, spin decay length and transport path of drifting spins can be controlled by electrical means in a single device. We also observed a drift-induced change in the spin precession period for drifting electron spins by visualizing the spatial distribution of electron spins. This phenomenon results from the cubic term of the Dresselhaus SOI enhanced by the application of in-plane electric fields . Our finding will be of great importance for a deeper understanding of spin transport dynamics as well as for relevant spintronics applications using an in-plane electric field.
 Y. Kunihashi et al., Nat. Commun. 7, 10722 (2016).
 Y. Kunihashi et al., Phys. Rev. Lett. 119, 187703 (2017).