Nuclear spin diffusion in semiconductor nanostructures: Effects of inhomogeneous hyperfine interactions

TL;DR

This paper investigates how inhomogeneous hyperfine interactions in semiconductor quantum dots suppress nuclear spin diffusion, combining theoretical calculations with experimental observations to clarify the underlying mechanisms.

Contribution

It provides a detailed analysis of the suppression of nuclear spin diffusion due to nonuniform hyperfine coupling in quantum dots, validating the method of moment in inhomogeneous systems.

Findings

Nuclear spin diffusion is strongly suppressed by inhomogeneous hyperfine interactions.

Results align with recent experimental observations of suppressed spin diffusion.

The method of moment's validity is clarified for inhomogeneous systems.

Abstract

We study the effect of contact hyperfine interaction on the nuclear spin diffusion coefficients in semiconductor quantum dots. The diffusion coefficients are calculated with both the method of moment and density matrix. We show that nuclear spin diffusion is strongly suppressed by the nonuniform hyperfine coupling resulting from the confined electron wavefunction. Our results agree with the observed suppression of nuclear spin diffusion in these structures in recent experiments, and clarify the degree of validity of the method of moment in an inhomogeneous system.