A study was made of the microstructure of (Ga,Mn)As-based digital ferromagnetic heterostructures, which nominally consisted of 40 periods of 0.75-monolayer Mn sheets between 17-monolayer GaAs spacer layers grown on GaAs(001) substrates by low-temperature molecular-beam epitaxy. Transmission electron microscopy studies revealed mainly stacking faults, which were preferentially coupled in V-shaped pairs with short intersecting lines along the [1¯10] direction. With increasing V/III beam equivalent pressure ratio, a stronger laterally inhomogeneous distribution of the Mn atoms was detected along the sheets, resulting in a larger local strain and thus in a higher density of stacking-fault pairs. Their anisotropic distribution was explained by energetically favorable Mn–As bonding configuration that was induced by the specific surface morphology appearing at the low growth temperature.

Anisotropic Distribution of Stacking Faults in (Ga,Mn)As Digital Ferromagnetic Heterostructures Grown by Low-Temperature Molecular-Beam Epitaxy. X.Kong, A.Trampert, X.X.Guo, L.Däweritz, K.H.Ploog: Journal of Applied Physics, 2005, 97[3], 036105 (3pp)