Engineering the electron g-factor anisotropy in double quantum wells

We investigate the quantum tunneling effects on the electron g factor and its main anisotropy in semiconductor double quantum wells (DQWs). With respect to single QWs, these structures introduce a new degree of freedom, given by the tunnel coupling parameter, and can be very helpful in the g-factor engineering. The eight-band effective-mass Hamiltonian for electrons in III-V double QWs and in the presence of an external magnetic field (applied both in the QW plane and along the growth direction) is solved for the g factor within first-order perturbation theory. We then calculate the g-factor anisotropy as a function of the QW width and the inter-well barrier length in typical AlGaAs/GaAs DQWs. The obtained results reproduce exactly the well-known single QW results in the corresponding limits, i.e. Lb=0 and very large, and explicitly show how the well-width dependence of the g-factor anisotropy changes with Lb, interpolating between these two limiting single QWs, with well width 2Lw and Lw respectively.