Effect of local Coulomb interactions on the electronic structure and exchange interactions in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Mn</mml:mi></mml:mrow><mml:mrow><mml:mn>12</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>magnetic molecules

Boukhvalov, Danil W.; Lichtenstein, A. I.; Dobrovitski, V. V.; Katsnelson, M. I.; Harmon, B. N.; Мазуренко, В. В.; Анисимов, В. И.

doi:10.1103/physrevb.65.184435

Cited by 78 publications

(72 citation statements)

References 44 publications

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“…Sophisticated ab initio techniques such as the GW approximation and local correlation methods such as DFT+U , whose traditional realm of application lies in extended systems such as extended oxides and their interfaces, are being increasingly applied to molecular systems and clusters (see for example Refs. 21,[44][45][46][47].…”

Section: Copper Phthalocyanine Dimermentioning

confidence: 99%

Subspace representations inab initiomethods for strongly correlated systems

2011

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We present a generalized definition of subspace occupancy matrices in ab initio methods for strongly correlated materials, such as DFT+U (density functional theory + Hubbard U ) and DFT+DMFT (dynamical mean-field theory), which is appropriate to the case of nonorthogonal projector functions. By enforcing the tensorial consistency of all matrix operations, we are led to a subspace-projection operator for which the occupancy matrix is tensorial and accumulates only contributions which are local to the correlated subspace at hand. For DFT+U , in particular, the resulting contributions to the potential and ionic forces are automatically Hermitian, without resort to symmetrization, and localized to their corresponding correlated subspace. The tensorial invariance of the occupancies, energies, and ionic forces is preserved. We illustrate the effect of this formalism in a DFT+U study using self-consistently determined projectors.

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Section: Copper Phthalocyanine Dimermentioning

confidence: 99%

Subspace representations inab initiomethods for strongly correlated systems

2011

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“…[17] Whereas bcc Fe shows Heisenberg behavior at the ferromagnetic (FM) state, MnFe alloys and FM Ni exhibit strong nonHeisenberg exchange mechanisms. 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.…”

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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“…An efficient scheme for the first-principle calculations of exchange interaction parameters in magnets based on a so-called "magnetic force theorem" (MFT) [1,2] in the density functional theory is frequently used for analysis of exchange parameters for different classes of magnetic materials such as dilute magnetic semiconductors [3], molecular magnets [4], colossal magnetoresistance perovskites [5], transition metal alloys [6], hard magnetic materials such as PtCo [7] and many others. Recently this method was generalized to take into account the correlation effects and successfully used for the quantitative estimation of exchange interactions in Fe and Ni [8,9].…”

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confidence: 99%

Magnetic susceptibility, exchange interactions and spin-wave spectra in the local spin density approximation

Katsnelson

Lichtenstein

2004

J. Phys.: Condens. Matter

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Starting from exact expression for the dynamical spin susceptibility in the time-dependent density functional theory a controversial issue about exchange interaction parameters and spin-wave excitation spectra of itinerant electron ferromagnets is reconsidered. It is shown that the original expressions for exchange integrals based on the magnetic force theorem (J. Phys. F 14 L125 (1984)) are optimal for the calculations of the magnon spectrum whereas static response function is better described by the "renormalized" magnetic force theorem by P. Bruno (Phys. Rev. Lett. 90 087205 (2003)). This conclusion is confirmed by the ab initio calculations for Fe and Ni.

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Effect of local Coulomb interactions on the electronic structure and exchange interactions inMn12magnetic molecules

Cited by 78 publications

References 44 publications

Subspace representations inab initiomethods for strongly correlated systems

Subspace representations inab initiomethods for strongly correlated systems

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

Magnetic susceptibility, exchange interactions and spin-wave spectra in the local spin density approximation

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