First-principles theory of dilute magnetic semiconductors

Satō, Kazunori; Bergqvist, Lars; Kudrnovský, J.; Dederichs, P. H.; Eriksson, Olle; Turek, I.; Sanyal, Biplab; Bouzerar, Georges; Katayama‐Yoshida, Hiroshi; Dinh, Van An; Fukushima, Tetsuya; Kizaki, Hidetoshi; Zeller, R.

doi:10.1103/revmodphys.82.1633

Cited by 1,033 publications

(806 citation statements)

References 209 publications

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“…The AFM and FM solutions are almost degenerate when the Co atoms are separated by this distance, indicating a very short-ranged character of the interatomic magnetic interactions. The tendency of clustering of the magnetic atoms is a general feature of transition-metal doped semiconductors, 21 and it motivates the study of trimers and tetramers, which we describe below.…”

Section: A Structural and Magnetic Propertiesmentioning

confidence: 99%

Microscopic picture of Co clustering in ZnO

et al. 2009

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Density functional theory was applied to study the chemical and magnetic interactions between Co atoms doped in ZnO. It was found that the Co impurities tend to form nanoclusters and the interactions between these atoms are antiferromagnetic within the local spin-density approximation ͑LSDA͒ + Hubbard U approach. The extracted interatomic exchange parameters agree reasonably well with recent experimental results. We have analyzed and compared the electronic structure obtained using the LSDA and LSDA+ U approaches and found that the LSDA+ U gives the most reasonable result, highlighting the importance of short-ranged antiferromagnetic interactions due to superexchange.

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Section: A Structural and Magnetic Propertiesmentioning

confidence: 99%

Microscopic picture of Co clustering in ZnO

et al. 2009

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“…The coupled spin-and charge-doping also creates difficulties in establishing the connection between host properties and figures of merit [13]. For example, a prediction of T C > 300 K in GaN:Mn [14] has stimulated a lot of efforts that turned out to be fruitless [15,16]. Finally, both substitutional and interstitial Mn are thermodynamically stable and form during synthesis, which additionally complicates theoretical treatment.…”

Section: Introduction-mentioning

confidence: 99%

Theory of Mn-doped II-II-V semiconductors

2014

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A recently discovered magnetic semiconductor Ba1−xKx(Zn1−yMny)2As2, with its decoupled spin and charge doping, provides a unique opportunity to elucidate the microscopic origin of the magnetic interaction and ordering in dilute magnetic semiconductors (DMS). We show that (i) the conventional density functional theory (DFT) accurately describes this material, and (ii) the magnetic interaction emerges from the competition of the short-range superexchange and a longer-range interaction mediated by the itinerant As holes, coupled to Mn via the Schrieffer-Wolff p−d interaction representing an effective Hund's rule coupling, J eff H . The key difference between the classical double exchange and the actual interaction in DMS is that an effective J eff H , as opposed to the standard Hund's coupling JH , depends on the Mn d−band position with respect to the Fermi level, and thus allows tuning of the magnetic interactions. The physical picture revealed for this transparent system may also be applicable to more complicated DMS systems.Introduction-The carrier-mediated magnetism in DMS [1-5] offers a versatile control of the exchange interaction by tuning the Curie temperature T C through changes in the carrier density [5][6][7][8]. However, despite four decades of intensive work, challenges remain and materials complexity often hinders theoretical understanding. The origin of magnetic ordering [1-3, 5] and paths to higher T C remain strongly debated [3,9,10].

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“…Besides the bulk systems, also finite systems such as the molecular magnets V 15 [18] and Mn 12 [19,20] have been studied. For both V 15 and Mn 12 , the exchange interactions between the antiferromagnetic (AFM)/ferrimagnetic and FM configuration differ by no more than 20-30%, a typical accuracy of the calculated Heisenberg model parameters in general. Furthermore, higher order exchange interactions such as biquadratic and ring exchange have been shown to lead to nonHeisenberg behavior in perovskite manganites.…”

Section: Introductionmentioning

confidence: 99%

“…[9][10][11] The MFT proved to be a powerful method for studying magnetic interactions from first principles. [12][13][14][15][16] The necessity of only a single magnetic state allows to study the applicability of the Heisenberg model by determining the dependence of the exchange interactions on the magnetic states.…”

Section: Introductionmentioning

confidence: 99%

Exchange interactions in transition metal oxides: the role of oxygen spin polarization

Logemann¹,

Руденко²,

Katsnelson³

et al. 2017

J. Phys.: Condens. Matter

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Abstract. Magnetism of transition metal (TM) oxides is usually described in terms of the Heisenberg model, with orientation-independent interactions between the spins. However, the applicability of such a model is not fully justified for TM oxides because spin polarization of oxygen is usually ignored. In the conventional model based on the Anderson principle, oxygen effects are considered as a property of the TM ion and only TM interactions are relevant. Here, we perform a systematic comparison between two approaches for spin polarization on oxygen in typical TM oxides. To this end, we calculate the exchange interactions in NiO, MnO, and hematite (Fe 2 O 3 ) for different magnetic configurations using the magnetic force theorem. We consider the full spin Hamiltonian including oxygen sites, and also derive an effective model where the spin polarization on oxygen renormalizes the exchange interactions between TM sites. Surprisingly, the exchange interactions in NiO depend on the magnetic state if spin polarization on oxygen is neglected, resulting in non-Heisenberg behavior. In contrast, the inclusion of spin polarization in NiO makes the Heisenberg model more applicable. Just the opposite, MnO behaves as a Heisenberg magnet when oxygen spin polarization is neglected, but shows strong non-Heisenberg effects when spin polarization on oxygen is included. In hematite, both models result in non-Heisenberg behavior. General applicability of the magnetic force theorem as well as the Heisenberg model to TM oxides is discussed.

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First-principles theory of dilute magnetic semiconductors

Cited by 1,033 publications

References 209 publications

Microscopic picture of Co clustering in ZnO

Microscopic picture of Co clustering in ZnO

Theory of Mn-doped II-II-V semiconductors

Exchange interactions in transition metal oxides: the role of oxygen spin polarization

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