Theory of orbital moment collapse under pressure in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">FeI</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Kuneš, J.; Rösner, H.; Kasinathan, Deepa; Rodríguez, C. O.; Pickett, Warren E.

doi:10.1103/physrevb.68.115101

Cited by 17 publications

(12 citation statements)

References 22 publications

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“…A different orbital occupation would lead to different orbital and dipolar hyperfine fields. This has not been examined any further in the present work, but it has been shown before that LDA + U can stabilize qualitatively different orbital occupations in iron compounds [131] and in lanthanide [121] compounds.…”

Section: Hyperfine Propertiesmentioning

confidence: 74%

The magnetization of γ′‐Fe₄N: theory vs. experiment

Blancá

Desimoni

Christensen

et al. 2009

Physica Status Solidi (b)

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By reviewing the experimental and theoretical literature on γ′‐Fe4N, and by a systematic survey of predictions by the LDA, PBE, WC, LDA + U (2×), PBE + U (2×) and B3PW91 exchange‐correlation functionals, the structural, magnetic and hyperfine properties of this material as well as their pressure dependencies are interpreted. The hypothesis is put forward that γ′‐Fe4N as found in Nature is exactly at a steep transition between low‐spin and high‐spin behaviour. PBE + U (U = 0.4 eV) is identified as the most accurate exchange‐correlation functional for this material, although it is needed to fix the magnetization at the experimental value to obtain a satisfying description. Remaining disagreement between theory and experiment is pointed out. A recent experimental claim for a giant magnetic moment in γ′‐Fe4N is discussed, and is not reproduced by our calculations. We expect that the new insight obtained in the present work can lead to a consistent ab initio modeling of other materials in the iron‐nitrogen binary system. In an accompanying didactic section, the physics behind some common exchange‐correlation functionals is outlined. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Hyperfine Propertiesmentioning

confidence: 74%

The magnetization of γ′‐Fe₄N: theory vs. experiment

Blancá

Desimoni

Christensen

et al. 2009

Physica Status Solidi (b)

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“…IP transition and the quenching of the orbital term take place at the same pressure range with no volume nor isomer shift (IS) change 3 [34] gives rather strong evidence that the observed lattice distortion in the c-direction, at the IP phase, is indeed attributed to the quenching of the orbital term. It is worth mentioning that Kunes et al [35], based on electronic structure calculations for FeI 2 , concluded that the quenching of the orbital term originates from a pressure-induced change of the sym-metry of the occupied minority-spin d-d orbital; namely, a change from a twofold-degenerate e 0 g orbital to a g occupation. The latter orbital is characterized by a very strong anisotropy of the charge and spin distribution, with the angular part stretched along the hexagonal c axis.…”

Section: A Case Of a Mott Transition Driven By An Increasing Crystal-mentioning

confidence: 99%

The Mott insulators at extreme conditions; structural consequences of pressure-induced electronic transitions

Rozenberg

Pasternak

2014

Zeitschrift Für Kristallographie – Crystalline Materials

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Electronic/magnetic transitions and their structural consequences in Fe-based Mott insulators in a regime of very high static density are the main issue of this short review paper. The paper focuses on the above-mentioned topics based primarily on our previous and ongoing experimental HP studies employing: (i) diamond anvil cells, (ii) synchrotron X-ray diffraction, (iii) 57 FeMössbauer spectroscopy, (iv) electrical resistance and (v) X-ray absorption spectroscopy. It is shown that applying pressure to such strongly correlated systems leads to a number of changes; including quenching of the orbital moment, quenching of Jahn-Teller distortion, spin crossover, inter-valence charge transfer, insulator-metal transition, moment collapse and volume collapse. These changes may occur simultaneously or sequentially over a range of pressures. Any of these may be accompanied by or be a consequence of a structural phase transition; namely, a change in crystal symmetry. Analyzing this rich variety of phenomena we show the main scenarios which such strongly correlated systems may undergo on the way to a correlation breakdown (Mott transition

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“…Since for U ¼ 0:5 and 0.6 Ry two different solutions were obtained and because it is possible to obtain many different solutions with LSDA þ U method depending on the initial density matrices, it seems appropriate to mention that the LSDA þ U total energies do not necessarily provide unambiguous criterion for the true ground state [9,38,39].…”

Section: Lsda-soc Calculationsmentioning

confidence: 99%