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MnSb nanocrystallites and thin films have been grown on highly oriented pyrolytic graphite (HOPG) by codeposition of Mn and Sb in ultrahigh vacuum. The surface morphologies of these MnSb structures were investigated using in situ scanning tunneling microscopy (STM). With 5 nm nominal deposition, MnSb nanocrystallite chains with a typical width of 50 nm are formed along the HOPG step edges. A continuous MnSb film is formed after Mn and Sb codeposition on a HOPG precovered with an Sb wetting layer. The MnSb thin film surface exhibits mostly hexagonal-shaped MnSb(0001) plateaus of a few atomic layers in height. Atomic-resolution STM images revealed 2×2 and (23×23)R30° reconstructions on the MnSb(0001) surface and a 2×1 superstructure on MnSb(1011). X-ray photoelectron spectroscopy study showed that the Mn 2p peaks shift 2.5 eV with respect to that of elemental Mn, indicating the formation of MnSb compound. Vibrating sample magnetometry measurement showed that the MnSb film is ferromagnetic at room temperature, and is composed of mostly (0001)-oriented grains as well as some with other orientations. [ABSTRACT FROM AUTHOR]

A structural model for GaAs(100)'s sulfur passivating layer contains dimeric S-Ga in a (2 x 1) superstructure on a complete Ga layer. The model's basis is experimental data and low energy electron diffraction studies. The structure has inherently stable electrostatic characteristics that induce good surface passivation.