Preparation of ferromagnetic (In,Mn)As with relatively low hole concentration and Curie temperature 50 K

Abstract

Ferromagnetic (In,Mn)As/GaSb and (In,Ga,Mn)As/GaSb heterostructures with Mn composition x=0.03–0.09 have been prepared by molecular beam epitaxy. It is found that the relation between maximum Curie temperature T C and Mn content x can be expressed experimentally by T C=800 x up to about T C=50 K within the limit of this study. The hole concentration sufficient for T C=50 K is found to be several times lower than the value shown in the existing theory (Science 287 (2000) 1049). Formation of structural pairs of Mn atoms (or few-atomic aggregates) in some close lattice sites is discussed to explain the observed results.