Unidirectional spin-orbit interaction and spin-helix state in a (110)-oriented GaAs/(Al,Ga)As quantum well

The Dresselhaus spin-orbit interaction is quantitatively investigated in a (110)-oriented GaAs quantum well by means of time- and spatially resolved Kerr rotation. The experimental results directly demonstrate a unidirectional out-of-plane spin-orbit interaction that linearly depends on the electron momentum along the [11¯0] direction and vanishes for the electron momentum along the [001] direction. Spatially resolved measurements of the diffusion-driven spin precession dynamics provide evidence of the formation of a persistent spin-helix state in this system.