An Exact SU(2) Symmetry and Persistent Spin Helix in a Spin-Orbit Coupled System

B. Andrei Bernevig, J. Orenstein, Shou-Cheng Zhang

Spin-orbit coupled systems generally break the spin rotation symmetry. However, for a model with equal Rashba and Dresselhauss coupling constant (the ReD model), and for the $[110]…