The effect of pressure on the electronic states of FeS and studied by Mössbauer spectroscopy

Kobayashi, Hisao; Sato, Masaki; Kamimura, Takashi; Sakai, Masamichi; Onodera, Hidetoshi; Kuroda, Noritaka; Yamaguchi, Yasuo

doi:10.1088/0953-8984/9/2/019

Cited by 55 publications

(56 citation statements)

References 16 publications

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“…A reversible electronic transition in FeS is closely related to the structural transition from a manganese phosphide-like phase to a monoclinic phase, with no sign of metallization at the transition [504]. The XES result is consistent with the disappearance of the magnetic splitting from Mössbauer spectroscopy [505]. Late transition metal oxides (MnO, FeO, CoO) are typical Mott insulators of charge-transfer type (U<).…”

Section: Spin-pairingsupporting

confidence: 58%

High-pressure studies with x-rays using diamond anvil cells

2016

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Pressure profoundly alters all states of matter. The symbiotic development of ultrahighpressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials' properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and magnetic properties of materials over a wide range of pressure-temperature conditions.

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Section: Spin-pairingsupporting

confidence: 58%

High-pressure studies with x-rays using diamond anvil cells

2016

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“…[1,21,22] However, there is an alternative scenario, which implies gradual metalization under pressure and the loss of the magnetic moments. [17,23] The absence of long range magnetic order in the high-pressure phase can be explained by electron delocalization: the increase of pressure results in the band broadening and in breaking of the Stoner criterion.…”

Section: +mentioning

confidence: 99%

“…[10] An abrupt breaking of long range magnetic order at room temperature is observed above 6.7 GPa. [10,16,17] This transition is accompanied by lattice volume collapse [6] and a change in the crystal symmetry (space group P 2 1 /a). The effective magnetic moment in Curie-Weiss theory, µ ef f , of FeS at ambient pressure is 5.5µ B .…”

Section: Introductionmentioning

confidence: 99%

Suppression of magnetism under pressure in FeS: A DFT+DMFT study

et al. 2017

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We investigate the evolution of the magnetic properties in FeS under pressure, and show that these cannot be explained solely in terms of the spin state transition from a high to low spin state due to an increase of the crystal field. Using a combination of density functional theory and dynamical mean field theory (DFT+DMFT), our calculations show that at normal conditions the Fe 2+ ions are in the 3d 6 high spin (S = 2) state, with some admixture of a 3d 7 L (S = 3/2) configuration, where L stands for the ligand hole. Suppressing the magnetic moment by uniform compression is related to a substantial increase in electron delocalization and occupation of several lower spin configurations. The electronic configuration of Fe ions cannot be characterized by a single ionic state, but only by a mixture of the 3d 7 L, 3d 8 L 2 , and 3d 9 L 3 configurations at pressures ∼ 7.5 GPa. The local spin-spin correlation function shows well-defined local magnetic moment, corresponding to a large lifetime in the high spin state at normal conditions. Under pressure FeS demonstrates a transition to a mixed state with small lifetimes in each of the spin configurations.

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“…In a simple metal, there also exist interactions connecting a large number of ions in addition to this force because of a nonlocal electron ion potential. The measurement of 57 Fe Mössbauer spectra was carried out under pressure [19]. It was found that the pressure dependence of the center shift changes significantly at 6.5 GPa.…”

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confidence: 99%

Phonon Density of States and Compression Behavior in Iron Sulfide under Pressure

et al. 2004

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We report the partial phonon densities of states (DOS) of iron sulfide, a possible component of the rocky planet's core, measured by the 57 Fe nuclear resonant inelastic x-ray scattering and calculate the total phonon DOS under pressure. From the phonon DOS, we drive thermodynamic parameters. A comparison of the observed and estimated compressibilities makes it clear that there is a large pure electronic contribution in the observed compressibility in the metallic state. Our results present the observation of thermodynamic parameters of iron sulfide with the low-spin state of an Fe 2 ion at the high density, which is similar to the condition of the Martian core. DOI: 10.1103/PhysRevLett.93.195503 PACS numbers: 63.20.-e, 71.30.+h, 76.80.+y, 91.60.Gf Iron sulfide, FeS, has been attracting attention in geosciences as well as condensed matter physics. The crystallographic properties of FeS have been investigated extensively at high pressures and/or high temperatures by x-ray diffraction measurements [1][2][3][4][5] because it is believed to be a component of the core of rocky planets such as Earth and Mars. Although the pressure vs temperature phase diagram has been contradictory, FeS undergoes two successive first-order phase transitions at room temperature, from the troilite (P 62c) to a MnP-type (Pnma) structure at 3.5 GPa and then to a monoclinic structure at 6.5 GPa with about 7% volume reduction. The compressibilities in those three phases were measured to be 13.6, 17.5, and 7:8 10 ÿ3 GPa ÿ1 , respectively. The thermodynamic properties under pressure are essential for understanding the core materials of the planets. However, there is no experimental knowledge of the lattice dynamics in FeS under pressure. Phonon dispersion relations and phonon densities of states (DOS) characterize the thermodynamic properties of the materials.At ambient conditions, FeS is an antiferromagnetic semiconductor with T N 589 K and belongs to the charge-transfer regime [6,7], where an electron correlation plays an important role. Electrical resistivity measurements of FeS under pressure [8] show that the semiconductor-metal and metal-semiconductor transitions occur at 3.5 and 6.5 GPa, respectively, corresponding to the structural phase transitions at room temperature. The energy gap in the semiconductor state below 3.5 GPa is caused by the electronic correlation, while the gap opens up between the nonbonding and antibonding bands in the semiconductor above 6.5 GPa. These phase transitions cause simultaneous changes in the electronic and structural properties. Therefore, we need to investigate the phonon properties of FeS in each phase and around these phase transitions from both the geophysics and condensed matter physical points of view. A new method based on nuclear resonant inelastic x-ray scattering (NRIXS) was introduced to measure partial phonon DOS in samples containing suitable Mössbauer nuclei [9,10]. Recently, this technique was successfully applied to measure the phonon DOS of "-Fe under pressure [11,12].In this Lette...

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The effect of pressure on the electronic states of FeS and studied by Mössbauer spectroscopy

Cited by 55 publications

References 16 publications

High-pressure studies with x-rays using diamond anvil cells

High-pressure studies with x-rays using diamond anvil cells

Suppression of magnetism under pressure in FeS: A DFT+DMFT study

Phonon Density of States and Compression Behavior in Iron Sulfide under Pressure

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