Electronic structures of Mn-induced phases on GaN(0001)

Abstract

We investigate the atomic and electronic structures of Mn-incorporated GaN͑0001͒ surface by scanning tunneling microscopy and first-principles calculations. The incorporation of Mn at room temperature initially leads to a disordered phase, and subsequently an ordered ͑3 ϫ 3͒ reconstruction at ϳ0.5 ML Mn coverage. The ͑3 ϫ 3͒ exhibits a honeycomb structure for sample bias below −0.5 V, and appears as a closed-packed structure above −1.2 V, which is attributed to antiferromagnetic ordering induced by Mn atoms. Incorporation of the same amount of Mn at an elevated substrate temperature of 300°C produces an additional phase with local ͑5 ϫ 5͒ periodicity, consisting of two types of trimers: one with three spots of equal intensity and the other with uneven intensities. This disparity in intensity can be resolved using a Fe-coated W tip, which is attributed to enhanced spin-dependent tunneling between the Mn-induced minority states and the Fe-induced states of the functionalized W tip.

Spinodal nanodecomposition in semiconductors doped with transition metals

“…Furthermore, well ordered Mn submonolayers have been deposited onto wz-GaN by evaporation (Chinchore et al, 2008) and (Ga,Mn)N nanostructures, though with a notinvestigated structure and actual composition, and grown by MOVPE onto GaN are reported (Gupta et al, 2006). A combined study by scanning tunneling microscopy (STM) and first-principles analysis states the feasibility of ordered Mn-induced nanostructures onto GaN(0001) at elevated temperatures, while the growth at RT leads to disordered phases (Qi et al, 2009). C. Co-doping with shallow impurities and δ-doping in (Ga,Mn)N As mentioned previously (Sec.…”

High-pressure synthesis of a new ferromagnetic compound, CrGa2Sb2

“…Chromium-doped and manganese-doped III-V semiconductor systems are widely investigated using molecular beam epitaxy (MBE) technique and many experimental studies revealed the ferromagnetism in these systems. Various structure models have been proposed to clarify the origin of ferromagnetism, including ordered structure model and the formation of secondary nano-cluster phase [4][5][6].…”

Ab-initio studies of the adsorption of a B ad-atom on GaN surfaces

“…In the BL-2 configuration, B atoms replace Ga atoms in a O3 Â O3-R301 arrangement within the first Ga layer, sending the replaced Gas into ad-atom positions. A similar model was proposed by Qi et al for their reported honeycomb structure of Mn on GaN (0001) [13]. We also considered the HD-1 model of Ref.…”