g-factor anisotropy of hole quantum wires induced by Rashba interaction

We present calculations of the g factors for the lower conductance steps of three-dimensional hole quantum wires. Our results prove that the anisotropy with magnetic field orientation, relative to the wire, originates in the Rashba spin-orbit coupling. We also analyze the relevance of the deformation, as the wire evolves from three-dimensional toward a flat two-dimensional geometry. For high enough wire deformations, the perpendicular g factors are greatly quenched by the Rashba interaction. On the contrary, parallel g factors are rather insensitive to the Rashba interaction, resulting in a high g-factor anisotropy. For low deformations, we find a more irregular behavior, which hints at a sample-dependent scenario.