Spin Exciton in quantum dot with spin orbit coupling in high magnetic field

TL;DR

This paper investigates the properties of a spin exciton in a quantum dot with strong magnetic field and spin-orbit coupling, revealing tunable excitations analogous to quantum Hall ferromagnets.

Contribution

It introduces a numerical study of spin exciton levels in quantum dots under high magnetic fields with Rashba spin-orbit coupling, highlighting their tunability and excitation mechanisms.

Findings

First excited state is a spin exciton with reversed spin at the origin.

Spin exciton level can be tuned with an electric field.

Infrared radiation can excite the spin exciton.

Abstract

Coulomb interactions of few ($ N $) electrons confined in a disk shaped quantum dot, with a large magnetic field $B=B^*$ applied in the z-direction (orthogonal to the dot), produce a fully spin polarized ground state. We numerically study the splitting of the levels corresponding to the multiplet of total spin $S=N/2$ (each labeled by a different total angular momentum $ J_z $) in presence of an electric field parallel to $ B $, coupled to $ S $ by a Rashba term. We find that the first excited state is a spin exciton with a reversed spin at the origin. This is reminiscent of the Quantum Hall Ferromagnet at filling one which has the skyrmion-like state as its first excited state. The spin exciton level can be tuned with the electric field and infrared radiation can provide energy and angular momentum to excite it.