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Substrate Information

Bulk GaAs exists in the zincblende structure with a polar (001) surface. The reconstruction of this surface is highly dependent on the growth conditions and surface stoichiometry. Reconstructions range from the As-rich c(4x4), to the Ga-rich (4x6) with (2x4), (6x6) and c(8x2) seen in between [16]. The introduction of Sb produces a variety of surfaces reconstructions depending on the original GaAs(001) surface reconstruction. The following references detail some of the combinations [17-21]. Growth of MnSb onto a GaAs(001) substrate has been studied by many groups and the important findings are summarised by Hatfield [5]. For a substrate temperature range relevant to this investigation, MnSb is found to match the NiAs crystal structure [22] in which close packed layers of Ni and As alternate to form an ABACAB... crystal (where A=Ni and B, C = As).

While a lot of research exists with regards to ferromagnet growth on III-V semiconductors with the zincblende structure [23, 24], such as GaAs, less is known about growth onto semiconductors with the diamond structure. Both Si and Ge crystals form in the diamond shape, which is described as two interpenetrating face-centred cubic primitive lattices [25]. At room temperature, Si and Ge (001) surfaces reconstruct into a 2x1 unit cell consisting of surface dimers [26, 27]. Sb deposition has been investigated on both surfaces and reconstructs into a 2x1 structure of Sb dimers [28, 29]. Little research exists into growth of MnSb on these surfaces, although some references were found [30].