Spin splitting and precession in quantum dots with spin-orbit coupling: the role of spatial deformation

TL;DR

This paper investigates how small elliptical deformations in quantum dots affect spin precession and splitting due to spin-orbit coupling, providing analytical and numerical insights that align with experimental observations.

Contribution

It introduces a detailed analysis of deformation effects on spin dynamics in quantum dots, including approximate formulas and numerical results for various spin-orbit couplings.

Findings

Deformation significantly alters spin precession at low magnetic fields.

Approximate expressions for the g factor are derived for weak spin-orbit coupling.

Numerical calculations match experimental spin-splitting data.

Abstract

Extending a previous work on spin precession in GaAs/AlGaAs quantum dots with spin-orbit coupling, we study the role of deformation in the external confinement. Small elliptical deformations are enough to alter the precessional characteristics at low magnetic fields. We obtain approximate expressions for the modified $g$ factor including weak Rashba and Dresselhaus spin-orbit terms. For more intense couplings numerical calculations are performed. We also study the influence of the magnetic field orientation on the spin splitting and the related anisotropy of the $g$ factor. Using realistic spin-orbit strengths our model calculations can reproduce the experimental spin-splittings reported by Hanson et al. (cond-mat/0303139) for a one-electron dot. For dots containing more electrons, Coulomb interaction effects are estimated within the local-spin-density approximation, showing that many features of the non-iteracting system are qualitatively preserved.