A class of striped superstructures with local hexagonal ordering has been obtained by depositing submonolayer Mn on the GaN(0001) surface. Combining scanning tunneling microcopy and firstprinciples theory, we find that Mn atoms incorporate into the surface and form a high-density twodimensional MnxGa1−x structure. The highly spin-polarized Mn d-electrons are found to dominate the surface electronic states. For the narrowest stripes, we calculate a row-wise antiferromagnetic ground state, which is observed in real-space at room temperature as a spin-induced asymmetry in the density of states. These two-dimensional magnetic structures on GaN can also be considered model systems for wide band-gap magnet/semiconductor spin injectors.
The authors report the growth of iron nitride on zinc-blende gallium nitride using molecular beam epitaxy. First, zinc-blende GaN is grown on a magnesium oxide substrate having ͑001͒ orientation; second, an ultrathin layer of FeN is grown on top of the GaN layer. In situ reflection high-energy electron diffraction is used to monitor the surface during growth, and a well-defined epitaxial relationship is observed. Cross-sectional transmission electron microscopy is used to reveal the epitaxial continuity at the gallium nitride-iron nitride interface. Surface morphology of the iron nitride, similar to yet different from that of the GaN substrate, can be described as plateau valley. The FeN chemical stoichiometry is probed using both bulk and surface sensitive methods, and the magnetic properties of the sample are revealed.
Practical applications of semiconductor spintronic devices necessitate ferromagnetic behavior at or above room temperature. In this paper, we demonstrate a two-dimensional manganese gallium nitride surface structure (MnGaN-2D) which is atomically thin and shows ferromagnetic domain structure at room temperature as measured by spin-resolved scanning tunneling microscopy and spectroscopy. Application of small magnetic fields proves that the observed magnetic domains follow a hysteretic behavior. Two initially oppositely oriented MnGaN-2D domains are rotated into alignment with only 120 mT and remain mostly in alignment at remanence. The measurements are further supported by first-principles theoretical calculations which reveal highly spin-polarized and spin-split surface states with spin polarization of up to 95% for manganese local density of states.
Articles you may be interested inStudying the formation of nitrogen δ-doped layers on GaAs(001) using reflection high-energy electron diffraction J.Submonolayer quantities of Mn are deposited on wurtzite GaN ͑0001͒. The surface is monitored using reflection high energy electron diffraction, which shows a pattern consisting of 3ϫ reconstruction along ͓1010͔, but only 1ϫ along ͓1120͔. Diffraction analysis shows that the 3ϫ streak intensity is maximized at Ϸ0.86 monolayer of Mn deposition. The results indicate that Mn forms linear chains along the ͓1010͔ direction with a spacing of ͱ 3a / 2 along chains and 3a / 2 between chains. Correcting the peak coverage for sticking coefficient and accounting for the observed periodicities, a ͱ 3 ϫ ͱ 3-R30°model, consisting of 2/3 monolayer of Mn atoms, is proposed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.