Tuning of the spin-orbit interaction in a quantum dot by an in-plane magnetic field

TL;DR

This paper investigates how an in-plane magnetic field influences spin-orbit interactions in InAs quantum dots, revealing anisotropic effects and providing a method to determine the relative strength of Rashba and Dresselhaus interactions.

Contribution

It demonstrates the anisotropic dependence of avoided crossing widths on magnetic field orientation and offers a way to extract the ratio of Rashba and Dresselhaus spin-orbit couplings.

Findings

Avoided crossing widths depend strongly on magnetic field orientation.

Certain magnetic field orientations eliminate avoided crossings.

Analysis explains recent experimental observations.

Abstract

Using an exact diagonalization approach we show that one- and two-electron InAs quantum dots exhibit avoided crossing in the energy spectra that are induced by the spin-orbit coupling in the presence of an in-plane external magnetic field. The width of the avoided crossings depends strongly on the orientation of the magnetic field which reveals the intrinsic anisotropy of the spin-orbit coupling interactions. We find that for specific orientations of the magnetic field avoided crossings vanish. Value of this orientation can be used to extract the ratio of the strength of Rashba and Dresselhaus interactions. The spin-orbit anisotropy effects for various geometries and orientations of the confinement potential are discussed. Our analysis explains the physics behind the recent measurements performed on a gated self-assembled quantum dot [S. Takahashi et al. Phys. Rev. Lett. 104, 246801 (2010)].