Theoretical study of nuclear spin polarization and depolarization in self-assembled quantum dots

TL;DR

This study explores how strain-induced nuclear quadrupole interactions affect nuclear spin polarization in self-assembled quantum dots, revealing dependencies on indium concentration and strain, with results aligning with experimental observations.

Contribution

It provides a theoretical analysis of nuclear spin polarization influenced by quadrupole interactions and strain in quantum dots, highlighting the relationship with indium concentration and magnetic fields.

Findings

Nuclear spin polarization depends on indium concentration and strain distribution.

Quadrupole interaction and Zeeman splitting influence magnetic field dependence.

Results qualitatively agree with experimental measurements.

Abstract

We investigate how the strain-induced nuclear quadrupole interaction influences the degree of nuclear spin polarization in self-assembled quantum dots. Our calculation shows that the achievable nuclear spin polarization in In_{x}Ga_{1-x}As quantum dots is related to the concentration of indium and the resulting strain distribution in the dots. The interplay between the nuclear quadrupole interaction and Zeeman splitting leads to interesting features in the magnetic field dependence of the nuclear spin polarization. Our results are in qualitative agreement with measured nuclear spin polarization by various experimental groups.