Microscopic characteristics of dynamic nuclear polarization and selective nuclear depolarization at the ν = 2/3 spin phase transition

The ability to manipulate the nuclear spin degree of freedom in semiconductor quantum structures is necessary for development of nuclear spintronics based on solid-state systems. Here, we developed a method to selectively depolarize the nuclear spin, the 〈+I _z〉 or the 〈-I _z〉 component, residing in a GaAs quantum well specimen after dynamic nuclear polarization by applying radio frequency pulse to either spin-unpolarized or spin-polarized nuclear magnetic resonance lines obtained at the spin transition of the filling ν = 2/3. Our results are evidence that the spin-unpolarized (spin-polarized) domain mediates the 〈+I _z〉 (〈-I _z〉) nuclear spin polarization.