Spin transverse separation in a two-dimensional electron-gas using an external magnetic field with a topological chirality

Abstract

We propose a two-dimensional electron-gas (2DEG) system in which an external magnetic field with a small chirality is applied to provide a topological spin gauge field that separates conduction electrons of opposite spins in the transverse direction. Additionally, the vertical electric field in the 2DEG, together with spin-orbit coupling, produces a SU(2) gauge field which reinforces or opposes the effect of the spin gauge. The system thus provides a tunable spin separation effect, where an applied gate voltage on the 2DEG can be used to modulate the transverse spin current. As this method leads to the enhancement or cancellation of spin separation due to the intrinsic spin-orbit coupling effect only, it may naturally distinguish the extrinsic effect from the intrinsic one. © 2008 The American Physical Society.