GaMnAs grown on (311) GaAs substrates: modified Mn incorporation and new magnetic anisotropies

TL;DR

This study investigates how growing GaMnAs on (311) GaAs substrates affects its structural, magnetic, and transport properties, revealing new magnetic anisotropies and growth efficiencies that could enhance Curie temperatures.

Contribution

It provides new insights into Mn incorporation efficiency and magnetic anisotropies in GaMnAs grown on (311) substrates, suggesting routes to improve magnetic properties.

Findings

Higher Curie temperature and hole density on (311)B compared to (001) substrates.

Evidence of more efficient Mn incorporation on (311)B surfaces.

Observation of new magnetic anisotropies, including biaxial and uniaxial components.

Abstract

We report the results of a detailed study of the structural, magnetic and magnetotransport properties of as-grown and annealed Ga0.91Mn0.09As thin films grown on (311)A and (311)B GaAs substrates. The high Curie temperature and hole density of the (311)B material are comparable to those of GaMnAs grown on (001) GaAs under the same growth conditions, while they are much lower for the (311)A material. We find evidence that Mn incorporation is more efficient for (311)B than for (001) and significantly less efficient for (311)A which is consistent with the bonding on these surfaces. This indicates that growth on (311)B may be a route to increased Curie temperatures in GaMnAs. A biaxial magnetic anisotropy is observed for the (311) material with easy axes along the [010] and [001] out-of-plane directions. An additional uniaxial in-plane anisotropy is also observed with the easy axis along for the (311)A material, and along for the (311)B material. This new observation may be of importance for the resolution of the outstanding problem of the origin of uniaxial anisotropy in (001) GaMnAs.