Exchange parameters of strongly correlated materials: Extraction from spin-polarized density functional theory plus dynamical mean-field theory

Kvashnin, Yaroslav; Grånäs, Oscar; Marco, Igor Di; Katsnelson, M. I.; Lichtenstein, A. I.; Eriksson, Olle

doi:10.1103/physrevb.91.125133

Cited by 120 publications

(114 citation statements)

References 62 publications

(136 reference statements)

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“…The so-called muffin-tin head projection scheme was applied to construct the set of localized Cr-d orbitals (for more details see Ref. [42]). The J ij 's were extracted from both ferromagnetic and antiferromagnetic configurations.…”

Section: Dft Computational Methodsmentioning

confidence: 99%

Magnetoelectric properties of multiferroic CuCrO2 studied by means of ab initio calculations and Monte Carlo simulations

et al. 2017

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Motivated by the discovery of multiferroicity in the geometrically frustrated triangular antiferromagnet CuCrO2 below its Néel temperature TN , we investigate its magnetic and ferroelectric properties using ab initio calculations and Monte Carlo simulations. Exchange interactions up to the third nearest neighbors in the ab plane, inter-layer interaction and single ion anisotropy constants in CuCrO2 are estimated by series of density functional theory calculations. In particular, our results evidence a hard axis along the [110] direction due to the lattice distortion that takes place along this direction below TN . Our Monte Carlo simulations indicate that the system possesses a Néel temperature TN ≈ 27 K very close to the ones reported experimentally (TN = 24 − 26 K). Also we show that the ground state is a proper-screw magnetic configuration with an incommensurate propagation vector pointing along the [110] direction. Moreover, our work reports the emergence of spin helicity below TN which leads to ferroelectricity in the extended inverse Dzyaloshinskii-Moriya model. We confirm the electric control of spin helicity by simulating P -E hysteresis loops at various temperatures.

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Section: Dft Computational Methodsmentioning

confidence: 99%

Magnetoelectric properties of multiferroic CuCrO2 studied by means of ab initio calculations and Monte Carlo simulations

et al. 2017

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“…Surprisingly, dynamical electron correlations using LSDA+DMFT lead only to small corrections in the exchange interactions compared to LSDA+U (J 1 = −0.03 meV and J 2 = −6.8 meV) for NiO and static local correlations capture most of the essential modifications. [42] Among the different methods, the J 1 interaction shows a spread of 0.7 meV. However, from the experimental point of view, the magnitude and even sign of J 1 remain uncertain.…”

Section: Niomentioning

confidence: 99%

“…The simple rock-salt structure along with the inability of regular DFT functionals to correctly describe these materials, make NiO and MnO typical benchmark systems to test methods for the calculation of exchange interactions in strongly correlated systems. Beyond the DFT methods such as LDA+U, [34,44,45] hybrid functionals, [46,47] the self-interaction correction, [41,48] GW approximation [49] and dynamical mean-field theory [42,50] have been used successfully to improve the correspondence between calculations and experiments in these materials. [34,42,46,47] In contrast, LSIC overestimates the electron localization, leading to a slight underestimation of the exchange interactions.…”

Section: Niomentioning

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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“…This contribution is much stronger in our case, and it overcomes the FM part of the exchange. Similar competition was shown to take place for the next NN exchange couplings in bulk Fe, which corresponds to the same coordination shell that we investigate here [41]. However, the balance between the two contributions can be easily changed by small changes in the NN distance.…”

Section: The (001) Surfacementioning

confidence: 76%

“…[41]. For the sake of simplicity, relativistic effects will not be considered in our work unless explicitly stated.…”

Section: Theorymentioning

confidence: 99%

Layer-resolved magnetic exchange interactions of surfaces of late3delements: Effects of electronic correlations

et al. 2015

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We present the results of an ab initio study of the magnetic properties of Fe, Co, and Ni surfaces. In particular, we discuss their electronic structure and magnetic exchange interactions (J ij ), as obtained by means of a combination of density functional theory and dynamical mean-field theory. All studied systems have a pronounced tendency to ferromagnetism both for bulk and surface atoms. The presence of narrowband surface states is shown to enhance the magnetic moment as well as the exchange couplings. The most interesting results were obtained for the Fe surface where the atoms have a tendency to couple antiferromagnetically with each other. This interaction is relatively small when compared to interlayer ferromagnetic interaction, and it depends strongly on the lattice parameter. Local correlation effects are shown to lead to strong changes of the overall shape of the spectral functions. However, they seem not to play a decisive role in the overall picture of magnetic couplings studied here. We have also investigated the influence of correlations on the spin and orbital moments of bulklike and surface atoms. We found that dynamical correlations in general lead to enhanced values of the orbital moment.

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Exchange parameters of strongly correlated materials: Extraction from spin-polarized density functional theory plus dynamical mean-field theory

Cited by 120 publications

References 62 publications

Magnetoelectric properties of multiferroic CuCrO2 studied by means of ab initio calculations and Monte Carlo simulations

Magnetoelectric properties of multiferroic CuCrO2 studied by means of ab initio calculations and Monte Carlo simulations

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

Layer-resolved magnetic exchange interactions of surfaces of late3delements: Effects of electronic correlations

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