Extrinsic Substrate Orientation Dependence of Ferromagnetism in (Ga, Mn)As Digital Ferromagnetic Heterostructures

摘要

We describe the structural and magnetic properties of digital ferromagnetic heterostructures of (Ga,Mn)As grown on (001), (311), (201) and (110) GaAs surfaces. Our measurements show a systematic variation of the Curie temperature with epitaxial orientation for samples with a nominally identical structure. Control measurements of randomly alloyed (Ga,Mn)As grown on these substrates show identical trends in Curie temperature, suggesting that the substrate orientation plays a strong role in the formation of hole-compensating defects in this ferromagnetic semiconductor.