Magnetic Form Factor of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Co</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>Ion in Cobaltous Oxide

Khan, D. C.; Erickson, R. A.

doi:10.1103/physrevb.1.2243

Cited by 85 publications

(29 citation statements)

References 27 publications

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“…This is identical to the usual superexchange philosophy [ 121. Our approach is therefore consistent with the existence of spin waves, and with the existence of four spin sublattices within the ground state of COO [23].…”

Section: ( I )supporting

confidence: 57%

“…Here the Co++ wave function consists mainly of a linear combination of three determinants, based on the three ways of choosing two out of the three t2g 4 orbitals: (xy, xz), (xy, yz), and (xz, yz). There is strong evidence that this is indeed the correct form of the Co++ ground state in COO, namely, the detailed success of the crystal-field interpretation of the optical excitons [31], and the unusually large orbital contribution to the magnetic moment [23,36,371. This implies that the simplest acceptable wave function for bulk COO must consist of 3 determinants, all of which are degenerate according to the elementary crystal-field model.…”

Section: B the Crystal-field Degeneracy Problem-coomentioning

confidence: 91%

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Theory of mott insulators

Brandow

2009

Int. J. Quantum Chem.

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The main characteristics of Mott insulator materials are qualitatively explained by means of a suitable form of Hartree-Fock approximation. This can be regarded as an extension of the Slater antiferromagnetic band theory. Semiquantitative applications to NiO and COO are described. The aspects discussed include the insulating gap, origin of the antiferromagnetic spin coupling, reasons for the validity of the crystal-field model, 3d bandwidth questions, and a survey of the basic microscopic mechanisms responsible for related insulatormetal transitions.

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Section: ( I )supporting

confidence: 57%

Section: B the Crystal-field Degeneracy Problem-coomentioning

confidence: 91%

Theory of mott insulators

Brandow

2009

Int. J. Quantum Chem.

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“…In the lowest stable magnetic structures, the O atom prefers to be in an outer position rather than in the center of the cluster. Thus, while for the Co 12 O cluster the substitution of the inner Co atom with an O atom does not lead to a stable magnetic structure, and geometry optimization results in being the O atom in an external position, for the Co 18 O cluster, results in a stable magnetic structure (figure 4, e structure), but it is located very high, at 3.3 eV above the lowest in energy structure. For the case of the Co 12 O a symmetric no magnetic structure (a) has been calculated, see figure 3, but when magnetic calculations were carried out, this structure was not stable and it was turned out to the stable magnetic structure b, where the symmetry is broken.…”

Section: Co X-1 O Clusters X = 13 14 and 19mentioning

confidence: 99%

“…The lowest calculated magnetic structures are depicted in figures 2-4 along with the energy differences from the lowest in energy magnetic structure. Three minima are given for the Co 12 O cluster, two for the Co 13 O cluster and 5 for the Co 18 O cluster. In the lowest stable magnetic structures, the O atom prefers to be in an outer position rather than in the center of the cluster.…”

Section: Co X-1 O Clusters X = 13 14 and 19mentioning

confidence: 99%

“…While the bulk Co and CoO material and their magnetic properties have been thoroughly studied experimentally, see for instance [10][11][12][13][14][15][16][17][18][19][20], and theoretically, via density functional theory (DFT) and Monte Carlo simulations, see for instance [21][22][23][24], attention has not been given yet for small clusters of Co-O. Moreover, while the Co/CoO system has been widely studied experimentally [9,[25][26][27], there is not any theoretical study.…”

Section: Introductionmentioning

confidence: 99%

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Magnetism in the interface of Co/CoO

Tzeli

Morphis

Blackman

et al. 2014

EPJ Web of Conferences

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Abstract.We have employed first-principles calculations to study the magnetic properties of the binary system Co-O. Two types of calculations were carried out: i. Co-O clusters of 13, 14 and 19 atoms and ii. Co/CoO bilayer. The Co/CoO bilayer forms a ferromagnetic-antiferromagnetic interface. The geometrical structures of the clusters and of the Co/CoO bilayer were optimized via ab initio collinear and non-collinear calculations. The spin-orbit interaction was included, too. We found that the addition of the O atom in the Co cluster leads to an increase of the μ Co values of O's adjacent Co atoms. At the bilayer, the Co atoms in the interface have enhanced magnetic moment compared to the corresponding values of the bulk Co in agreement with the experiment.

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DFT‐based solution to the gap problem of antiferromagnetic transition metal oxides and parent compounds of high‐T_c superconductors

Fritsche

Pérez-Jiménez

Reinert

2002

Int J of Quantum Chemistry

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ABSTRACT:Currently used approximations to the exchange-correlation potential in density functional theory (DFT) are known to fail in describing the properties of certain compounds, of which we discuss here only two examples: CoO and stoichiometric La 2 CuO 4 . Both materials are insulating and antiferromagnetic. A DFT calculation on CoO yields antiferromagnetic order, but Co-associated magnetic moments that are by ϳ1 B smaller than the experimental value, and one obtains the electronic structure of a metal. The latter applies also to La 2 CuO 4 , and, in contrast to the experiment, the calculation does not even yield nonzero moments associated with the Cu atoms. We exploit the fact that approximate exchange-correlation potentials lead necessarily to spin-dependent densities that differ from the exact ones. We therefore derive modified Kohn-Sham (KS) equations in which the effective potentials depend on the exact spin densities rather than on the standard KS densities. If the latter are modified by adding small (spin-up, spin-down) portions that individually integrate to zero within the lattice unit cell and do not change the total charge density, the inconsistencies with the experiment can be removed.

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Magnetic Form Factor ofCo++Ion in Cobaltous Oxide

Cited by 85 publications

References 27 publications

Theory of mott insulators

Theory of mott insulators

Magnetism in the interface of Co/CoO

DFT‐based solution to the gap problem of antiferromagnetic transition metal oxides and parent compounds of high‐T_c superconductors

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Magnetic Form Factor ofCo++Ion in Cobaltous Oxide

Cited by 85 publications

References 27 publications

Theory of mott insulators

Theory of mott insulators

Magnetism in the interface of Co/CoO

DFT‐based solution to the gap problem of antiferromagnetic transition metal oxides and parent compounds of high‐Tc superconductors

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Product

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DFT‐based solution to the gap problem of antiferromagnetic transition metal oxides and parent compounds of high‐T_c superconductors