Optical and magnetic measurements of <i>p</i>-type GaN epilayers implanted with Mn+ ions

Shon, Yoon; Kwon, Yongchai; Yuldashev, Sh. U.; Leem, J. H.; Park, C. S.; Fu, Dejun; Kim, H. J.; Kang, Tae Won; Fan, Xuejun

doi:10.1063/1.1506778

Cited by 78 publications

(43 citation statements)

References 6 publications

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“…In order to explain the origin of ferromagnetism in DMS as well as the values of the Curie temperature the meanfield Zener model was employed, where the ordering of spins results from the p -d kinetic exchange interaction [2] between magnetic ions and the delocalised or weakly localized holes. The theoretical work triggered significant experimental efforts, but the results are to date rather controversial, being the highest claimed Curie temperature of 270 K for GaN:Mn [3] to be possibly attributed to various Mn x N y phases [4]. Furthermore, ab initio calculations based on the local-spin-density approximation [5] obtain a deep Mn 3+/2+ acceptor and Mn 3+/ 4+ donor level in GaN, which would hinder the presence of free electron or free holes in GaN:Mn [6].…”

Section: Introductionmentioning

confidence: 97%

Doping of GaN with Fe and Mg for spintronics applications

Bonanni

Simbrunner

Wegscheider

et al. 2006

Physica Status Solidi (b)

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Metal-organic chemical vapour deposition of GaN : Fe and (Ga, Fe)N : Mg has been carried out in order to optimize the growth process and to investigate the effectiveness of Fe ions and Mg acceptors incorporation. All samples have been investigated via high-resolution X-ray diffraction, secondary-ion mass spectroscopy, electron paramagnetic resonance (EPR) and magnetization measurements. Co-doping of Fe and δ -Mg has been found to promote the acceptors incorporation and EPR data, supported by superconducting quantum interference device magnetometry experiments, reveal the presence of Fe ions in two charge states, namely the Fe 3+ responsible for Curie paramagnetism and the Fe 2+ tentatively correlated to van Vleck paramagnetism.

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Section: Introductionmentioning

confidence: 97%

Doping of GaN with Fe and Mg for spintronics applications

Bonanni

Simbrunner

Wegscheider

et al. 2006

Physica Status Solidi (b)

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“…Five Ga 1−x Mn x N films are described here, (A: 300 nm, x = 0.003; B: 300 nm, x = 0.005; C: 1000 nm, x = 0.01; D: 1000 nm, x = 0.012; E: 1200 nm, x = 0.015). To provide a standard for comparison, samples of MOCVD-grown p-type (p = 2 × 10 16 cm −3 ) and intrinsic GaN were ion-implanted with Mn concentrations of 3 × 10 16 cm −2 at an energy of 200 keV and a substrate temperature of 400…”

Section: Methodsmentioning

confidence: 99%

Magnetic and optical properties of Ga_1−xMn_xN grown by metalorganic chemical vapour deposition

Kane

Asghar

Vestal

et al. 2005

Semicond. Sci. Technol.

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Epitaxial layers of Ga 1−x Mn x N with concentrations of up to x = 0.015 have been grown on c-sapphire substrates by metalorganic chemical vapour deposition. No ferromagnetic second phases were detected via high-resolution x-ray diffraction. Crystalline quality and surface structure were measured by x-ray diffraction and atomic force microscopy, respectively. No significant deterioration in crystal quality and no increase in surface roughness with the incorporation of Mn were detected. Optical measurements show a broad emission band attributed to a Mn-related transition at 3.0 eV that is not seen in the underlying GaN virtual substrate layers. Room temperature ferromagnetic hysteresis has been observed in these samples, which may be due to either Mn-clustering on the atomic scale or the Ga 1−x Mn x N bulk alloy.

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“…On the other hand, available experimental data often contradict each other. Some reports show that high T c ferromagnetism is achievable in this system [2,3,4,5]; others show that the magnetic coupling of the Mn ions in GaMnN is actually antiferromagnetic (AFM) [6]. The exact nature of the magnetism observed in this system is also still under debate [7,8,9].…”

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confidence: 99%

Transition from ferromagnetism to antiferromagnetism in Ga1−xMnxN

Dalpian

Wei

2005

Journal of Applied Physics

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Using density functional theory, we study the magnetic stability of the Ga1−xMnxN alloy system. We show that unlike Ga1−xMnxAs, which shows only ferromagnetic (FM) phase, Ga1−xMnxN can be stable in either FM or antiferromagnetic phases depending on the alloy concentration. The magnetic order can also be altered by applying pressure or with charge compensation. A unified model is used to explain these behaviors.The discovery of ferromagnetism in Mn-containing III-V semiconductors has attracted significant attention in the last decade because the interesting combination of semiconductor electronics and metallic ferromagnetism creates great potential for developing functional devices that manipulate spin, as well as charge. Among the materials that have been investigated, GaMnN is one of the most interesting systems. On one hand, original theoretical predictions suggest that high T c ferromagnetism can be achieved in the GaMnN alloy [1], which has resulted in an extensive experimental, as well as theoretical, study of its physical properties. On the other hand, available experimental data often contradict each other. Some reports show that high T c ferromagnetism is achievable in this system [2,3,4,5]; others show that the magnetic coupling of the Mn ions in GaMnN is actually antiferromagnetic (AFM) [6]. The exact nature of the magnetism observed in this system is also still under debate [7,8,9]. Some groups suggested that the observed ferromagnetism could be due to secondary phases generated during growth, and that GaMnN is a spin glass system [8]. Other groups argue that no secondary phase is observed in their single-crystal GaMnN samples that show ferromagnetism [9]. There are also discussions about whether the relevant Mn 3d state has d 4 or d 5 + h character, or whether the d levels are localized in the bandgap or inside the valence band [10].Although many of the issues are still under intensive study, recent ab initio band structure and total energy calculations [11,12,13] seem to agree that Mn 3d levels are located in the gap, and that the interaction between substitutional Mn ions is ferromagnetic (FM) at low Mn concentration. Because previous ab initio studies also find that pure MnN has an AFM ground state [14], an interesting question was raised about how the magnetic and electronic properties of Ga 1−x Mn x N evolve as a function of the Mn concentration x. Furthermore, it is now well known that the ferromagnetism observed in Mn-containing GaAs is caused by holes in the host valence-band-derived states. It would be important to understand how the mechanism changes in Mn-containing GaN, where the holes are created in the Mn d bands.In this paper, using ab initio band structure and total energy methods, we study the magnetic properties of Ga 1−x Mn x N in the low and high Mn concentration regimes. We also study the effects of pressure and charge compensation on the magnetic properties of this system. We show that unlike in GaMnAs, where p-d coupling induced level splitting at the valence band maximum (VBM)...

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Optical and magnetic measurements of p-type GaN epilayers implanted with Mn+ ions

Cited by 78 publications

References 6 publications

Doping of GaN with Fe and Mg for spintronics applications

Doping of GaN with Fe and Mg for spintronics applications

Magnetic and optical properties of Ga_1−xMn_xN grown by metalorganic chemical vapour deposition

Transition from ferromagnetism to antiferromagnetism in Ga1−xMnxN

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Optical and magnetic measurements of p-type GaN epilayers implanted with Mn+ ions

Cited by 78 publications

References 6 publications

Doping of GaN with Fe and Mg for spintronics applications

Doping of GaN with Fe and Mg for spintronics applications

Magnetic and optical properties of Ga1−xMnxN grown by metalorganic chemical vapour deposition

Transition from ferromagnetism to antiferromagnetism in Ga1−xMnxN

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Magnetic and optical properties of Ga_1−xMn_xN grown by metalorganic chemical vapour deposition