Significant g-factor values of a two-electron ground state in quantum dots with spin-orbit coupling

TL;DR

This study explores how spin-orbit coupling influences the magnetization and g-factor in two-electron quantum dots, revealing a level crossing and ground-state magnetization that could impact experimental measurements.

Contribution

It demonstrates that spin-orbit coupling induces a significant g-factor and ground-state magnetization in two-electron quantum dots, highlighting a novel interaction effect.

Findings

Level crossing between lowest many-body states occurs with increasing spin-orbit coupling.

Ground-state magnetization becomes non-zero due to level crossing.

The g-factor can reach significant values, affecting measurements.

Abstract

The magnetization of semiconductor quantum dots in the presence of spin-orbit coupling and interactions is investigated numerically. When the dot is occupied by two electrons we find that a level crossing between the two lowest many-body eigenstates may occur as a function of the spin-orbit coupling strength. This level crossing is accompanied by a non-vanishing magnetization of the ground-state. Using first order perturbation theory as well as exact numerical diagonalization of small clusters we show that the tendency of interactions to cause Stoner-like instability is enhanced by the SO coupling. The resulting g-factor can have a significant value, and thus may influence g-factor measurements. Finally we propose an experimental method by which the predicted phenomenon can be observed.