Structural and magnetic evidence of confined strain fields in GaMnAs grown on ordered arrays of zero-dimensional nanostructures

TL;DR

This study demonstrates how ordered arrays of quantum dots induce localized strain fields in GaMnAs films, which in turn modulate their magnetic properties, offering a new method for nanoscale control of magnetic anisotropy.

Contribution

It provides experimental evidence of strain modulation in GaMnAs via quantum dot arrays and links this to changes in magnetic anisotropy, a novel approach for nanoscale magnetic control.

Findings

Quantum dots induce periodic tensile and compressive strains in GaMnAs.

Strain increases as dots are spaced closer together.

Magnetization anisotropy correlates with strain variations.

Abstract

We prepared Ga0.95Mn0.05As films on top of periodic arrays of InAs quantum dots. X-ray diffraction reveals periodically strained films, commensurate to substrate's patterning. The dots produce a tensile strain in GaMnAs while between the dots strain is compressive. Our experiments confirm that the average tensile strain in the film increases with decreasing dots separation. This trend in strain is accompanied by an increase of the out-of-plane magnetization component familiar from the established relation between strain and magnetic anisotropy in GaMnAs films. Our work provides a new route for controlling magneto-crystalline anisotropies in GaMnAs on a nanometer scale.