Dynamical formation and manipulation of persistent spin helices in two-dimensional electron gases

The spin-orbit interaction in two-dimensional electron gases is responsible for a broad range of phenomena, including spin Hall effects and spin textures such as the persistent spin helix (PSH). A PSH occurs when parameters associated with the bulk (Dresselhaus) and structural (Rashba) inversion asymmetries are roughly equal in strength. This situation results in a momentum-dependent effective magnetic field providing the SU(2) symmetry in which the two-dimensional electron gas (2DEG) features a unidirectional spin grating (or helical spin-density wave). Here I will focus on several new aspects of PSH formation and manipulation obtained from temporally and spatially resolved Kerr microscopy.