Control of electron spin dynamics in a wide GaAs quantum well by a lateral confining potential

The spin dynamics of electrons laterally confined in a wide GaAs quantum well with the use of a special mosaic electrode deposited onto the sample plane has been investigated. Comparative measurements with a semitransparent electrode have been simultaneously carried out to distinguish changes in electron spin dynamics due to the band bending from those due to the lateral confinement controlled by applying an external bias. The electron spin lifetimes in the traps has been found to increase strongly with the applied bias. The measured values of the electron $g$-factor in the quantum well plane and the magnetic-field dependence of the electron spin lifetimes indicate the emergence of strong three-dimensional confinement in the center of an orifice in the mosaic electrode. The examined electron spin relaxation anisotropy is caused by the anisotropy of the confining potential.