Spin-relaxation anisotropy in a nanowire quantum dot with strong spin-orbit coupling

TL;DR

This paper investigates how magnetic field direction affects spin manipulation and relaxation in a one-dimensional quantum dot with strong spin-orbit coupling, revealing periodic behaviors in transition and relaxation rates.

Contribution

It provides an exact solution for the energy spectrum and eigenfunctions, and uncovers the periodicity differences in spin relaxation rates across coupling regimes.

Findings

Electric-dipole spin transition rate always has π periodicity.

Phonon-induced spin relaxation rate's periodicity depends on spin-orbit coupling strength.

Periodicities shift from π to 2π as spin-orbit coupling becomes strong.

Abstract

We study the impacts of the magnetic field direction on the spin-manipulation and the spin-relaxation in a one-dimensional quantum dot with strong spin-orbit coupling. The energy spectrum and the corresponding eigenfunctions in the quantum dot are obtained exactly. We find that no matter how large the spin-orbit coupling is, the electric-dipole spin transition rate as a function of the magnetic field direction always has a $\pi$ periodicity. However, the phonon-induced spin relaxation rate as a function of the magnetic field direction has a $\pi$ periodicity only in the weak spin-orbit coupling regime, and the periodicity is prolonged to $2\pi$ in the strong spin-orbit coupling regime.