Electrically tunable effective g -factor of a single hole in a lateral GaAs/AlGaAs quantum dot

Electrical tunability of the $$g$$-factor of a confined spin is a long-time goal of the spin qubit field. Here we utilize the electric dipole spin resonance (EDSR) to demonstrate it in a gated GaAs double-dot device confining a hole. This tunability is a consequence of the strong spin-orbit interaction (SOI) in the GaAs valence band. The SOI enables a spin-flip interdot tunneling, which, in combination with the simple spin-conserving charge transport leads to the formation of tunable hybrid spin-orbit molecular states. EDSR is used to demonstrate that the gap separating the two lowest energy states changes its character from a charge-like to a spin-like excitation as a function of interdot detuning or magnetic field. In the spin-like regime, the gap can be characterized by the effective $$g$$-factor, which differs from the bulk value owing to spin-charge hybridization, and can be tuned smoothly and sensitively by gate voltages. Coherent control is a necessity in semiconductors spintronics. The authors use electric dipole spin resonance to control a GaAs double quantum dot demonstrating electrical tunability of the Zeeman splitting, enabling local qubit control within short time compared to the spin coherence time.