Light-induced Knight shifts in GaAs/AlGaAs quantum wells

Abstract

The coupling between quantum-confined electron spins in semiconductor heterostructures and nuclear spins dominates the dephasing of spin qubits in III/V semiconductors. The interaction can be measured through the electron-spin dynamics or through its effect on the nuclear spin. Here, we discuss the resulting shift of the NMR frequency (the Knight shift) and measure its size as a function of the charge-carrier density for photoexcited charge carriers in a GaAs quantum well.