Strong electrically tunable exciton g-factors in an individual quantum dots due to hole orbital angular momentum quenching

TL;DR

This study demonstrates strong electrical control of exciton g-factors in individual quantum dots, primarily through hole orbital angular momentum quenching, with simulations supporting the experimental findings.

Contribution

It reveals the microscopic origin of g-factor tunability in quantum dots, emphasizing the role of hole wavefunction perturbation and providing design insights for spin manipulation.

Findings

G-factor tunability is dominated by the hole, with weak electron contribution.

Electric fields impact the hole wavefunction via orbital angular momentum quenching.

Simulations accurately reproduce experimental observations for realistic quantum dot models.

Abstract

Strong electrically tunable exciton g-factors are observed in individual (Ga)InAs self-assembled quantum dots and the microscopic origin of the effect is explained. Realistic eight band k.p simulations quantitatively account for our observations, simultaneously reproducing the exciton transition energy, DC Stark shift, diamagnetic shift and g-factor tunability for model dots with the measured size and a comparatively low In-composition of x(In)~35% near the dot apex. We show that the observed g-factor tunability is dominated by the hole, the electron contributing only weakly. The electric field induced perturbation of the hole wavefunction is shown to impact upon the g-factor via orbital angular momentum quenching, the change of the In:Ga composition inside the envelope function playing only a minor role. Our results provide design rules for growing self-assembled quantum dots for electrical spin manipulation via electrical g-factor modulation.