Enhanced longevity of the spin helix in low-symmetry quantum wells

In two-dimensional electron gases, optimally tuned linear Rashba and Dresselhaus spin-orbit couplings enable the emergence of a persistent spin helix. While such a spin texture has an extremely high durability and robustness, its lifetime is still limited due to the unavoidable influence of the cubic Dresselhaus spin-orbit coupling. Here, the authors investigate the possibility to minimize this unwanted effect by altering the quantum-well orientation. It is demonstrated that a low-symmetry growth direction is ideal for enhancing the spin-helix lifetime.