Spin-orbit coupling and anisotropy of spin splitting in quantum dots

TL;DR

This paper investigates how combined Dresselhaus and Rashba spin-orbit couplings cause anisotropic spin splitting in quantum dots, revealing the dominant mechanism through experimental measurements and analysis.

Contribution

It provides experimental analysis of spin splitting anisotropy in quantum dots to identify the dominant spin-orbit coupling mechanism.

Findings

Measured spin splitting anisotropy in quantum dots.

Determined the dominant spin-orbit coupling mechanism.

Analyzed the effect of external magnetic field orientation.

Abstract

In lateral quantum dots, the combined effect of both Dresselhaus and Bychkov-Rashba spin orbit coupling is equivalent to an effective magnetic field B_so which has the opposite sign for s_z=1/2 spin electrons. When the external magnetic field is perpendicular to the planar structure, the field B_so generates an additional splitting for electron states as compared to the spin splitting in the in-plane field orientation. The anisotropy of spin splitting has been measured and then analyzed in terms of spin-orbit coupling in several AlGaAs/GaAs quantum dots by means of resonanat tunneling spectroscopy. From the measured values and sign of the anisotropy we are able to determine the dominating spin-orbit coupling mechanism.