Optical orientation of electron spins by linearly polarized light

TL;DR

This paper demonstrates that in semiconductor quantum wells, linearly polarized light can induce electron spin orientation, with the spin direction controllable by rotating the light's polarization plane, due to quantum well symmetry and spin splitting effects.

Contribution

It reveals a novel method of spin orientation in quantum wells using linearly polarized light, expanding the understanding beyond circular polarization effects.

Findings

Spin orientation achieved with linearly polarized light in quantum wells

Spin direction controllable by rotating polarization plane

Effect linked to quantum well symmetry and spin splitting

Abstract

Absorption of circularly polarized light in semiconductors is known to result in optical orientation of electron and hole spins. It has been shown here that in semiconductor quantum well structures spin orientation of carriers can be achieved by linearly or even unpolarized light. Moreover, the sign and magnitude of the spin orientation can be varied by rotating the polarization plane of incidence light. The effect under study is related to reduced symmetry of the quantum wells as compared to bulk materials and, microscopically, caused by zero-field spin splitting of electron and hole states.