Anomalous Hanle curves induced by in-plane nuclear field in single self-assembled InAlAs and InAs nanostructures

Abstract

We studied the formation mechanism of in-plane nuclear field by anomalous Hanle effect measurements in single self-assembled In0.75Al0.25As/Al0.3Ga0.7As quantum dots and InAs/GaAs quantum rings. The observed anomalous Hanle curves indicated quite large width and hysteretic behavior to the externally applied magnetic field. These anomalies appears in both materials whose electron g factors have opposite sign each other, and cannot be reproduced by a traditional spin dynamics model. In this study, we show that a proposed spin dynamics model can explain the formation of a large in-plane nuclear field regardless of the sign of electron g factor. The model is based on the dynamic nuclear spin polarization mechanism including the effects of nuclear quadrupole interaction.