Valence transition in polycrystalline Eu(Rh 1–x Co x ) 2 Si 2  studied by hard x-ray photoemission spectroscopy

Ichiki, Katsuya; Matsumoto, Takayuki; Anzai, H.; Takeshita, Ryohei; Abe, K.; Ishihara, Suzuna; Uozumi, Takayuki; Sato, Hitoshi; Rousuli, Awabaikeli; Ueda, Shigenori; Taguchi, Y.; Shimada, Kenya; Namatame, H.; Takeuchi, Masaki; Mitsuda, Akihiro; Wada, Hirofumi; Mimura, Koji

doi:10.1016/j.elspec.2017.03.014

Cited by 2 publications

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“…Our valence band spectra give an explanation to the robust Eu 2+ magnetic states against pressure. The dominant part of the Eu 4f DOS of EuT Ge 3 is localized at ∼1 eV below E F which is deeper than other Eucompounds possessing an intermediate Eu valence state or valence transition 29,48 . It hinders a charge transfer from Eu 4f to the conduction band that make up the valence fluctuation or non-magnetic Eu 3+ states.…”

Section: Resultsmentioning

confidence: 87%

“…Broad structures around 1140 and 1170 eV are attributed to plasmon statellites related to the Eu 2+ 3d photoemission process. Compared to the Eu 3d spectrum of other divalent Eu compounds, such as EuRh 2 Si 2 (mean-Eu valence v ∼ 2.1 at 300-20 K) 29 and EuNi 2 (Si 0.21 Ge 0.79 ) 2 (v ∼ 2.2 at 300 K) 30 , the relative intensity of Eu 3+ components to those of Eu 2+ is small and buried in the tail of the Eu 2+ components and its statellite structures. As expected from magnetic susceptibility and Mössbauer measurements, the Eu valence states in the EuT Ge 3 series are very close to Eu 2+ .…”

Section: Resultsmentioning

confidence: 90%

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Bulk electronic structure of non-centrosymmetric EuTGe3 ( T=Co , Ni, Rh, Ir) studied by hard x-ray photoelectron spectroscopy

et al. 2018

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Non-centrosymmetric EuT Ge3 (T =Co, Ni, Rh, and Ir) possesses magnetic Eu 2+ ions and antiferromagnetic ordering appears at low temperatures. Transition metal substitution leads to changes of the unit cell volume and of the magnetic ordering. However, the magnetic ordering temperature does not scale with the volume change and the Eu valence is expected to remain divalent. Here we study the bulk electronic structure of non-centrosymmetric EuT Ge3 (T =Co, Ni, Rh, and Ir) by hard x-ray photoelectron spectroscopy. The Eu 3d core level spectrum confirms the robust Eu 2+ valence state against the transition metal substitution with a small contribution from Eu 3+ . The estimated Eu mean-valence is around 2.1 in these compounds as confirmed by multiplet calculations. In contrast, the Ge 2p spectrum shifts to higher binding energy upon changing the transition metal from 3d to 4d to 5d elements, hinting of a change in the Ge-T bonding strength. The valence bands of the different compounds are found to be well reproduced by ab initio band structure calculations.

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Section: Resultsmentioning

confidence: 87%

Section: Resultsmentioning

confidence: 90%

Bulk electronic structure of non-centrosymmetric EuTGe3 ( T=Co , Ni, Rh, Ir) studied by hard x-ray photoelectron spectroscopy

et al. 2018

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Electronic Structure of the Valence Transition System Eu(Rh₁₋_xT_x)₂Si₂ (T = Co, Ir) Studied by High-Energy Resolution Fluorescence Detection X-Ray Absorption Spectroscopy

Shimokasa

Kawamura

Taku

et al. 2020

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)

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The electronic structure of Eu(Rh 1-x T x) 2 Si 2 (T = Co, Ir) showing a valence change with temperature has been investigated by means of high-energy resolution fluorescence detection X-ray absorption spectroscopy (HERFD-XAS). The Eu L 3-edge HERFD-XAS spectra for Eu(Rh 1-x T x) 2 Si 2 distinctly demonstrate that, due to the improvement of the energy resolution, the intensities of Eu 2+ and Eu 3+ components are dependent on temperature. Each component has additional fine structures, which clearly change above and below the transition temperature. These spectral changes are similar to those for EuNi 2 (Si 1-x Ge x) 2 , but the degree of temperature dependence on energy difference between Eu 2+ and Eu 3+ components is different from EuNi 2 (Si 1-x Ge x) 2. The results of this study suggest that a treatment of the many-body interaction is essential to understanding the valence transition of Eu compounds.

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Valence transition in polycrystalline Eu(Rh 1–x Co x ) 2 Si 2 studied by hard x-ray photoemission spectroscopy

Cited by 2 publications

References 18 publications

Bulk electronic structure of non-centrosymmetric EuTGe3 ( T=Co , Ni, Rh, Ir) studied by hard x-ray photoelectron spectroscopy

Bulk electronic structure of non-centrosymmetric EuTGe3 ( T=Co , Ni, Rh, Ir) studied by hard x-ray photoelectron spectroscopy

Electronic Structure of the Valence Transition System Eu(Rh₁₋_xT_x)₂Si₂ (T = Co, Ir) Studied by High-Energy Resolution Fluorescence Detection X-Ray Absorption Spectroscopy

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Valence transition in polycrystalline Eu(Rh 1–x Co x ) 2 Si 2 studied by hard x-ray photoemission spectroscopy

Cited by 2 publications

References 18 publications

Bulk electronic structure of non-centrosymmetric EuTGe3 ( T=Co , Ni, Rh, Ir) studied by hard x-ray photoelectron spectroscopy

Bulk electronic structure of non-centrosymmetric EuTGe3 ( T=Co , Ni, Rh, Ir) studied by hard x-ray photoelectron spectroscopy

Electronic Structure of the Valence Transition System Eu(Rh1−xTx)2Si2 (T = Co, Ir) Studied by High-Energy Resolution Fluorescence Detection X-Ray Absorption Spectroscopy

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Electronic Structure of the Valence Transition System Eu(Rh₁₋_xT_x)₂Si₂ (T = Co, Ir) Studied by High-Energy Resolution Fluorescence Detection X-Ray Absorption Spectroscopy