Lifetime of spin-orbit induced spin textures in a semiconductor heterostructure probed by quantum corrections to conductivity

The persistent spin helix (PSH) is the stable spin state protected by SU(2) spin-rotation symmetry. Long-lived spin textures, referred to as helical and homogeneous spin modes, emerge as a result of this symmetry. These textures are potential candidates for the development of quantum and topological phenomena as well as information carriers in semiconductors. To this end, revealing the lifetime of all spin modes is of great importance. We experimentally reveal the lifetime of both helical and homogeneous spin modes in the vicinity of the PSH state by fully electrical means through quantum corrections to the conductivity. In a (001)-grown GaAs/AlGaAs two-dimensional electron gas, we measure the weak antilocalization in the condition where Rashba and Dresselhaus spin-orbit (SO) interactions coexist. According to the latest theory on magnetoconductance [Kammermeier et al., Phys. Rev. B 104, 235430 (2021)], the Cooperon triplet mode in the quantum corrections can be decoupled into helical and homogeneous spin modes in the vicinity of the PSH state, which allows each mode lifetime to be determined from the quantum interference effect. By using a real-space simulation in tandem with the experiment, we were able to simultaneously evaluate the relaxation rates of the two spin modes. Our results show that the ratio of Rashba and Dresselhaus SO coefficients is modulated by the top gate and that this quadratically changes the relaxation rates of the helical and homogeneous spin modes, which is consistent with theoretical predictions. These findings pave the way for exploring electron spin textures in various bandgap materials from semiconductors to metals.