Photoinduced dynamics in quantum rings

TL;DR

This paper studies how spin-dependent electronic responses in quantum rings are affected by electromagnetic pulses and spin orbit interaction, revealing spin-dependent dipole moments and induced charge and spin currents.

Contribution

It demonstrates the influence of spin orbit interaction on dynamical responses and introduces the concept of an effective SU(2) flux affecting spin-dependent phenomena.

Findings

Pulse-generated electric dipole moments are spin dependent.

Spin orbit interaction induces an additional SU(2) effective flux.

Electromagnetic pulses can induce net charge and spin currents.

Abstract

We investigate the spin-dependent dynamical response of a semiconductor quantum ring with a spin orbit interaction (SOI) upon the application of a single and two linearly polarized, picosecond, asymmetric electromagnetic pulses in the presence of a static magnetic flux. We find that the pulse-generated electric dipole moment is spin dependent. It is also shown that the SOI induces an extra SU(2) effective flux in addition to the static external magnetic flux which is reflected in an additional periodicity of the spin-dependent dipole moment. Furthermore, the pulses may induce a net dynamical charge currents (CC) and dynamical spin currents (SC) when the clockwise and anti-clockwise symmetry of the carrier is broken upon the pulse application.