Anisotropic spin interference in InGaAs/InAlAs rectangular loop arrays

We report the experimental detection of the anisotropic spin-orbit interaction (SOI) in InGaAs/InAlAs quantum wells, using spin interference experiments in arrays of rectangular loops with their sides aligned to the [1 1 0] and [11¯0] crystallographic directions. While the gate voltage is tuned, the time reversal Aharonov-Casher (TRAC) oscillations exhibit higher frequencies when the loops have their longer side along the [1 1 0] direction, clearly highlighting the anisotropy of the SOI. We find that a simple spin interferometer model, including both the Rashba and the Dresselhaus SOIs, reproduces qualitatively the TRAC oscillations.