Fabrication and properties of GaAsSb/GaAs heterostructures doped with a magnetic impurity

Structures made up of a GaAsSb/GaAs quantum well (QW) and $\delta$-layers of manganese and carbon in the GaAs cap layer have been grown and studied for the first time. The resulting heteronanostructures have good crystal perfection, which is confirmed by X-ray diffraction analysis and photoluminescence studies. It was found that, at temperatures below 20–25 K, the heteronanostructures have ferromagnetic properties as they exhibit nonlinear magnetic-field dependences of the Hall resistance and a negative magnetoresistance. Profiling of the elemental composition by secondary ion mass spectrometry revealed the opposite effect of $\delta$ doping the GaAs cap layer with carbon and manganese on the profile of the GaAsSb QW: the introduction of carbon makes the GaAsSb/GaAs heterointerface less abrupt due to the segregation of antimony, whereas doping with manganese hardly affects the antimony distribution profile in the QW.