Physics Commons^™

Emergence Of The Persistent Spin Helix In Semiconductor Quantum Wells, J. D. Koralek, Christopher P. Weber, J. Orenstein, B. Andrei Bernevig, Shou-Cheng Zhang, S. Mack, D. D. Awschalom

Physics

According to Noether’s theorem¹, for every symmetry in nature there is a corresponding conservation law. For example, invariance with respect to spatial translation corresponds to conservation of momentum. In another well-known example, invariance with respect to rotation of the electron’s spin, or SU(2) symmetry, leads to conservation of spin polarization. For electrons in a solid, this symmetry is ordinarily broken by spin–orbit coupling, allowing spin angular momentum to flow to orbital angular momentum. However, it has recently been predicted that SU(2) can be achieved in a two-dimensional electron gas, despite the presence of spin–orbit coupling². The …