Paramagnetism and antiferromagnetic d–d coupling in GaMnN magnetic semiconductor

Zając, M.; Gosk, J.; Kamińska, M.; Twardowski, A.; Szyszko, T.; Podsiadło, S.

doi:10.1063/1.1406558

Cited by 151 publications

(135 citation statements)

References 23 publications

(19 reference statements)

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“…However, other XAS studies [49][50][51] demonstrate that Mn is predominantly Mn 2+ (d 5 ). A similar conclusion was also reached by electron spin resonance [14] and magnetic measurements [15]. Clearly, a resolution of the uncertainty about the Mn valence state is imperative for further progress in the understanding and engineering of the Ga 1−x Mn x N DMS.…”

supporting

confidence: 49%

What is the Valence of Mn inGa1−xMnxN?

et al. 2015

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We investigate the current debate on the Mn valence in Ga1−xMnxN, a diluted magnetic semiconductor (DMSs) with a potentially high Curie temperature. From a first-principles Wannier-function analysis, we unambiguously find the Mn valence to be close to 2+ (d 5 ), but in a mixed spin configuration with average magnetic moments of 4µB. By integrating out high-energy degrees of freedom differently, we further derive for the first time from first-principles two low-energy pictures that reflect the intrinsic dual nature of the doped holes in the DMS: 1) an effective d 4 picture ideal for local physics, and 2) an effective d 5 picture suitable for extended properties. In the latter, our results further reveal a few novel physical effects, and pave the way for future realistic studies of magnetism. Our study not only resolves one of the outstanding key controversies of the field, but also exemplifies the general need for multiple effective descriptions to account for the rich low-energy physics in many-body systems in general.

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confidence: 49%

What is the Valence of Mn inGa1−xMnxN?

et al. 2015

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“…27) and in Ga 1-x Mn x N with free carrier concentration below 10 18 cm −3 J/k B equals -1.9 K(Ref. 28). These values are very similar to the values of J/k B observed here.…”

Section: Magnetic Propertiessupporting

confidence: 78%

Homogeneous limit of Cd1−xMnxGeAs2 alloy: Electrical and magnetic properties

Kilański

Górska

Dynowska

et al. 2014

Journal of Applied Physics

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We present the studies of structural, electrical, and magnetic properties of bulk Cd 1-x Mn x GeAs 2 crystals with low Mn content, x, varying from 0 to 0.037. The studied samples have excellent crystallographic quality indicated by the presence of diffraction patterns never before observed experimentally for this compound. The electrical transport in our samples is dominated by thermal activation of conducting holes from the impurity states to the valence band with activation energy of about 200 meV. The defect states acting as ionic scattering centers with concentration in the range from 6 to 15×10 17 cm −3 are observed. The effective Mn content in our samples,x θ , determined from fit of the susceptibility data to the Curie-Weiss law, is very close to the average chemical content, x. It indicates that the Mn ions are distributed randomly, substituting the Cd sites in the host CdGeAs 2 lattice. We observe a negative Curie-Weiss temperature, |θ| ≤ 3.1 K, increasing as a function of x. This indicates the significance of the short-range interactions between the Mn ions.

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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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Paramagnetism and antiferromagnetic d–d coupling in GaMnN magnetic semiconductor

Abstract: Structural and magnetic properties of (Ga,Mn)N layers grown on SiC by reactive molecular beam epitaxy

Cited by 151 publications

References 23 publications

What is the Valence of Mn inGa1−xMnxN?

What is the Valence of Mn inGa1−xMnxN?

Homogeneous limit of Cd1−xMnxGeAs2 alloy: Electrical and magnetic properties

Transition from ferromagnetism to antiferromagnetism in Ga1−xMnxN

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