Gate-controlled anisotropy in Aharonov-Casher spin interference

The Aharonov-Casher (AC) effect shows that the quantum spin phase can be modified by an electric field. This effect is fundamental in quantum mechanics and its applications, where AC interferometers are invaluable to probe spin-phase information. We demonstrate a gate-controlled anisotropy in AC spin interferometry using InGaAs mesoscopic rings. The coexistence of Rashba and Dresselhaus spin-orbit interactions (SOIs) manifests as an AC resistance amplitude modulated by the direction of a probe in-plane magnetic field. We establish ways to manipulate spin dynamic and geometric phases freely by employing electric and magnetic tunings. Our experimental results are well explained by perturbation theory and numerical analysis performed at constant Dresselhaus SOI, except for one particular anisotropy reversal. The observation of such a particular AC anisotropy reversal is explained as sign change in linear Dresselhaus SOI by electric means.