Effect of annealing on the hyperfine interaction in InAs/GaAs quantum dots

TL;DR

This paper investigates how annealing affects the hyperfine interaction in InAs/GaAs quantum dots through numerical modeling and experimental validation, revealing the dominant role of indium nuclei at high annealing temperatures.

Contribution

It provides a detailed theoretical analysis of the hyperfine interaction changes due to annealing, including modeling of energy structure and nuclear contributions, validated by experimental data.

Findings

Indium nuclei dominate hyperfine interaction at high annealing temperatures.

Localization volume of electrons varies with annealing temperature.

Nuclear spin fluctuations significantly impact electron spin polarization.

Abstract

The hyperfine interaction of an electron with nuclei in the annealed self-assembled InAs/GaAs quantum dots is theoretically analyzed. For this purpose, the annealing process, and energy structure of the quantum dots are numerically modeled. The modeling is verified by comparison of the calculated optical transitions and of the experimental data on photoluminescence for set of the annealed quantum dots. The localization volume of the electron in the ground state and the partial contributions of In, Ga, and As nuclei to the hyperfine interaction are calculated as functions of the annealing temperature. It is established that the contribution of indium nuclei into the hyperfine interaction becomes predominant up to high annealing temperatures (T = 980 C) when the In content in the quantum dots does not exceed 25%. Effect of the nuclear spin fluctuations on the electron spin polarization is numerically modeled. Effective field of the fluctuations is found to be in good agreement with experimental data available.