pith. sign in

arxiv: 2510.00448 · v3 · submitted 2025-10-01 · ❄️ cond-mat.str-el · cond-mat.mtrl-sci

Possibility of ferro-octupolar order in Ba₂CaOsO₆ assessed by X-ray magnetic dichroism measurements

Pith reviewed 2026-05-18 11:16 UTC · model grok-4.3

classification ❄️ cond-mat.str-el cond-mat.mtrl-sci
keywords ferro-octupolar orderhidden orderBa2CaOsO6X-ray magnetic circular dichroism5d2 electronsligand-field multipletOs L edgedouble perovskite
0
0 comments X

The pith

X-ray magnetic circular dichroism indicates that a ferro-octupolar order in Ba2CaOsO6 would require a nearest-neighbor octupole exchange of about 1.5 meV.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper examines the hidden order below 50 K in the cubic double perovskite Ba2CaOsO6, which contains localized 5d2 electrons on Os6+ ions that can form electric quadrupoles and magnetic octupoles. X-ray absorption spectroscopy fixes the cubic ligand-field splitting at roughly 4 eV, while X-ray magnetic circular dichroism spectra are analyzed with ligand-field multiplet calculations performed under fictitious strong magnetic fields. These calculations show that a ferro-octupolar ordered state would be stabilized by an octupole exchange interaction of approximately 1.5 meV, matching earlier model and density-functional estimates of 1 meV. The temperature evolution of the spectra further supports an 18 meV residual splitting that places the non-Kramers Eg doublet as the ground state within the lowest Jeff = 2 multiplet. A sympathetic reader cares because this supplies an experimental route to quantify hidden multipolar orders that evade conventional magnetic probes.

Core claim

Ligand-field multiplet calculation under fictitious strong magnetic fields applied to the observed XMCD spectra indicates that the exchange interaction between nearest-neighbor octupoles should be as strong as ∼1.5 meV if a ferro-octupolar order is stabilized in the hidden-ordered state of Ba2CaOsO6, consistent with prior theoretical predictions of ∼1 meV, while the temperature dependence reveals a ∼18 meV residual cubic splitting of the lowest Jeff = 2 multiplet into an Eg doublet ground state and a T2g triplet.

What carries the argument

Ligand-field multiplet calculation under fictitious strong magnetic fields, which maps the measured dichroism at the Os L2,3 edges onto the implied strength of the nearest-neighbor octupolar exchange interaction.

If this is right

  • The deduced octupole exchange strength of ∼1.5 meV supports the theoretical models previously used to describe the hidden order.
  • The ∼4 eV cubic splitting confirms the expected ligand-field scale for Os6+ 5d2 ions in the double-perovskite environment.
  • The ∼18 meV residual splitting explains the observed temperature dependence of the XMCD signal through population of the Eg ground doublet.
  • XMCD under fictitious fields offers a practical experimental handle on the strength of multipolar interactions in other 5d2 systems.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • If the ferro-octupolar assignment holds, similar hidden-order phases in other 5d2 double perovskites could be tested by applying the same fictitious-field XMCD analysis.
  • Confirmation would link the hidden order to possible octupole-driven responses such as time-reversal-odd transport without net magnetization.
  • The 18 meV scale sets a concrete energy window for future inelastic neutron or Raman studies of the low-lying multiplet excitations.

Load-bearing premise

The hidden order below 50 K is assumed to be ferro-octupolar rather than antiferro-octupolar, quadrupolar, or another multipolar pattern, and the fictitious-field multiplet calculation correctly converts the dichroism into an exchange energy scale.

What would settle it

A neutron diffraction or resonant X-ray scattering experiment that detects antiferro-octupolar correlations or a different ground-state symmetry would contradict the ferro-octupolar interpretation used to extract the 1.5 meV value.

Figures

Figures reproduced from arXiv: 2510.00448 by Amol Singh, Arata Tanaka, Atsushi Fujimori, Chien-Te Chen, Di-Jing Huang, Goro Shibata, Hiroaki Hayashi, Hsiao-Yu Huang, Jun Okamoto, Kazunari Yamaura, Naomi Kawamura, Sergey V. Streltsov.

Figure 1
Figure 1. Figure 1: FIG. 1. Energy levels of the Os [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. XAS and XMCD spectra of Ba [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. Schematic drawing of the ferro-octupolar order of the [PITH_FULL_IMAGE:figures/full_fig_p004_4.png] view at source ↗
read the original abstract

Localized $5d^2$ electrons in a cubic crystal field possess multipoles such as electric quadrupoles and magnetic octupoles. We studied the cubic double perovskite Ba$_2$CaOsO$_6$ containing the Os$^{6+}$ ($5d^2$) ions, which exhibits a phase transition to a `hidden order' below $T^* \sim$ 50 K, by X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) at the Os $L_{2,3}$ edge. The cubic ligand-field splitting between the $t_{2g}$ and $e_g$ levels of Os $5d$ was deduced by XAS to be $\sim$4 eV. Ligand-field (LF) multiplet calculation under fictitious strong magnetic fields indicated that the exchange interaction between nearest-neighbor octupoles should be as strong as $\sim$1.5 meV if a ferro-octupolar order is stabilized in the `hidden-ordered' state, consistent with the exchange interaction of $\sim$1 meV previously predicted theoretically using model and density functional theory calculations. The temperature dependence of the XMCD spectra was consistent with a $\sim$18 meV residual cubic splitting of the lowest $J_{\rm eff} =$ 2 multiplet state into the non-Kramers $E_g$ doublet ground state and the $T_{2g}$ triplet excited state.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript reports X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) measurements at the Os L_{2,3} edges on the cubic double perovskite Ba₂CaOsO₆ containing 5d² Os⁶⁺ ions that undergo a hidden-order transition below T* ≈ 50 K. A ligand-field splitting of ∼4 eV between t_{2g} and e_g levels is extracted from the XAS data. Ligand-field multiplet calculations performed under fictitious strong magnetic fields are then used to relate the measured XMCD intensity to an effective molecular field, yielding an estimated nearest-neighbor octupolar exchange of ∼1.5 meV if ferro-octupolar order is realized in the hidden-ordered phase; this value is stated to be consistent with prior theoretical predictions of ∼1 meV. The temperature dependence of the XMCD spectra is interpreted as indicating a residual cubic splitting of ∼18 meV within the J_eff = 2 multiplet, separating a non-Kramers E_g doublet ground state from a T_{2g} triplet excited state.

Significance. If the central quantitative claim holds, the work supplies an experimental constraint on the strength of octupolar interactions in a 5d² hidden-order candidate, bridging XMCD data with independent model and DFT calculations. The explicit use of multiplet theory to map dichroism onto an effective exchange parameter, together with the reported numerical consistency between the deduced 1.5 meV and the earlier ∼1 meV theoretical value, constitutes a concrete strength that could help discriminate among candidate multipolar patterns in related materials.

major comments (2)
  1. [Ligand-field multiplet calculation under fictitious fields] Ligand-field multiplet calculation under fictitious fields: the conversion of the observed XMCD signal into the ∼1.5 meV nearest-neighbor octupolar exchange is load-bearing for the central claim yet omits the explicit mean-field mapping (including coordination number, coupling tensor, and induced octupole moment) and any propagated uncertainties; the abstract and main text should state the precise relation between fictitious-field strength and exchange constant.
  2. [Temperature dependence of XMCD spectra] Temperature dependence of XMCD spectra: the reported consistency with an 18 meV splitting of the J_eff = 2 multiplet constrains the single-ion ground state but does not independently validate the ferro-octupolar (versus antiferro-octupolar or quadrupolar) character of the order; additional justification or a falsifiable test for the assumed order pattern is required to support the exchange extraction.
minor comments (2)
  1. [Abstract] Abstract: the conditional nature of the 1.5 meV value on the ferro-octupolar assumption should be stated explicitly.
  2. [Notation] Notation: ensure consistent rendering of J_eff (or J_eff) and E_g / T_{2g} throughout the text and figures.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading and constructive comments on our manuscript. We address each major comment point by point below, indicating the revisions we will make.

read point-by-point responses
  1. Referee: Ligand-field multiplet calculation under fictitious fields: the conversion of the observed XMCD signal into the ∼1.5 meV nearest-neighbor octupolar exchange is load-bearing for the central claim yet omits the explicit mean-field mapping (including coordination number, coupling tensor, and induced octupole moment) and any propagated uncertainties; the abstract and main text should state the precise relation between fictitious-field strength and exchange constant.

    Authors: We agree that the mean-field mapping requires explicit statement. In the revised manuscript we will add a clear derivation: the fictitious field B_fict is applied within the ligand-field multiplet framework to induce an octupole moment, which is then related to the nearest-neighbor exchange J via the mean-field relation J = (B_fict / m_oct) / z, where z = 6 is the coordination number on the Os sublattice and m_oct is the calculated octupole expectation value. The assumed isotropic ferro-octupolar coupling tensor will be specified. Uncertainties arising from XMCD intensity and spectral fitting will be propagated and quoted. Both the abstract and main text will be updated to include this relation. revision: yes

  2. Referee: Temperature dependence of XMCD spectra: the reported consistency with an 18 meV splitting of the J_eff = 2 multiplet constrains the single-ion ground state but does not independently validate the ferro-octupolar (versus antiferro-octupolar or quadrupolar) character of the order; additional justification or a falsifiable test for the assumed order pattern is required to support the exchange extraction.

    Authors: The temperature dependence is used solely to establish the single-ion ground state (non-Kramers E_g doublet), which is a necessary condition for octupolar order. The ferro-octupolar assumption is adopted because it yields an exchange value consistent with independent model and DFT predictions of ∼1 meV. In revision we will add a paragraph discussing why antiferro-octupolar or quadrupolar scenarios are disfavored by the absence of conventional magnetic Bragg peaks and by the sign and magnitude of the extracted interaction. We acknowledge that a direct falsifiable test (e.g., resonant X-ray scattering) lies outside the present experiment and will state this limitation explicitly. revision: partial

Circularity Check

0 steps flagged

No significant circularity in derivation of octupolar exchange estimate

full rationale

The paper extracts the ~1.5 meV nearest-neighbor octupolar exchange value from measured Os L_{2,3} XMCD spectra by performing ligand-field multiplet calculations under fictitious magnetic fields that simulate the molecular field produced by assumed ferro-octupolar order. This is an interpretive modeling step that converts observed dichroism into an effective exchange parameter conditional on the order type; it does not reduce the output to the input by construction, nor does it rename a fit as a prediction. The XAS-derived ligand-field splitting (~4 eV) and the temperature-dependent XMCD consistency with an 18 meV J_eff=2 splitting are independent single-ion constraints. The result is compared to prior external model/DFT predictions for consistency but those citations are not load-bearing for the experimental claim. No self-definitional loop, self-citation chain, or ansatz smuggling is present in the reported chain.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 0 invented entities

The claim rests on the validity of ligand-field multiplet theory for 5d2 ions, the assumption that the hidden order is octupolar, and the mapping from fictitious magnetic field to real exchange interaction; no new particles or forces are postulated.

free parameters (2)
  • ligand-field splitting t2g-eg = ~4 eV
    Deduced directly from XAS line shape as ~4 eV
  • residual cubic splitting of Jeff=2 multiplet = ~18 meV
    Extracted from temperature dependence of XMCD intensity as ~18 meV
axioms (2)
  • domain assumption Localized 5d2 electrons in cubic crystal field form multipoles including magnetic octupoles
    Standard starting point for 5d2 ions in double perovskites
  • domain assumption The phase transition at T* ~50 K is to a hidden multipolar ordered state
    Taken from earlier thermodynamic and neutron studies of Ba2CaOsO6

pith-pipeline@v0.9.0 · 5862 in / 1597 out tokens · 42631 ms · 2026-05-18T11:16:00.155277+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Reference graph

Works this paper leans on

37 extracted references · 37 canonical work pages

  1. [1]

    Khomskii and S

    D. Khomskii and S. Streltsov, Orbital effects in solids: Basics, recent progress, and opportunities, Chemical Re- views121, 2992 (2021)

  2. [2]

    D. I. Khomskii and S. V. Streltsov, Magnetic oxides, in Encyclopedia of Condensed Matter Physics (Second Edi- tion), edited by T. Chakraborty (Academic Press, Ox- ford, 2024) second edition ed., pp. 98–111

  3. [3]

    B. J. Kim, H. Jin, S. J. Moon, J.-Y. Kim, B.-G. Park, C. S. Leem, J. Yu, T. Noh, C. Kim, S.-J. Oh, J.-H. Park, V. Durairaj, G. Cao, and E. Rotenberg, NovelJ eff=1/2 Mott state induced by relativistic spin-orbit coupling in Sr2IrO4, Phy. Rev. Lett.101, 076402 (2008)

  4. [4]

    B. J. Kim, H. Ohsumi, T. Komesu, S. Sakai, T. Morita, H. Takagi, and T. Arima, Phase-sensitive observation of a spin-orbital Mott state in Sr 2IrO4, Science323, 1329 (2009)

  5. [5]

    Y. K. Kim, O. Krupin, J. D. Denlinger, A. Bostwick, E. Rotenberg, Q. Zhao, J. F. Mitchell, J. W. Allen, and B. J. Kim, Fermi arcs in a doped pseudospin-1/2 Heisen- berg antiferromagnet, Science345, 187 (2009)

  6. [6]

    Suzuki, H

    H. Suzuki, H. Liu, J. Bertinshaw, K. Ueda, H. Kim, S. Laha, D. Weber, Z. Yang, L. Wang, H. Takahashi, K. F¨ ursich, M. Minola, B. V. Lotsch, B. J. Kim, H. Yava¸ s, M. Daghofer, J. Chaloupka, G. Khaliullin, H. Gretarsson, and B. Keimer, Proximate ferromagnetic state in the Ki- taev model materialα-RuCl 3, Nat. Commun.12, 4512 (2021)

  7. [7]

    Chen and L

    G. Chen and L. Balents, Spin-orbit coupling ind2 ordered double perovskites, Phys. Rev. B84, 094420 (2011)

  8. [8]

    Svoboda, W

    C. Svoboda, W. Zhang, M. Randeria, and N. Trivedi, Orbital order drives magnetic order in 5d1 and 5d2 double perovskite mott insulators, Phys. Rev. B104, 024437 (2020)

  9. [9]

    Paramekanti, D

    A. Paramekanti, D. D. Maharaj, and B. D. Gaulin, Oc- tupolar order ind-orbital Mott insulators, Phys. Rev. B 101, 054439 (2020)

  10. [10]

    Khaliullin, D

    G. Khaliullin, D. Churchill, P. P. Stavropoulos, and H.- Y. Kee, Exchange interactions, Jahn-Teller coupling, and multipole orders in pseudospin one-half 5d 2 Mott insula- tors, Phys. Rev. Res.3, 033163 (2021)

  11. [11]

    S. V. Streltsov and D. I. Khomskii, Jahn-Teller effect and spin-orbit coupling: Friends or foes?, Phys. Rev. X10, 031043 (2020)

  12. [12]

    C. M. Thompson, J. P. Carlo, R. Flacau, T. Aharen, I. A. Leahy, J. R. Pollichemi, T. J. S. Munsie, T. Medina, G. M. Luke, J. Munevar, S. Cheung, T. Goko, Y. J. Ue- mura, and J. E. Greedan, Long-range magnetic order in the 5d2 double perovskite Ba2CaOsO6: comparison with 6 spin-disordered Ba 2YReO6, J. Phys.: Condens. Matter 26, 306003 (2014)

  13. [13]

    R. Cong, E. Garcia, P. C. Forino, A. Tassetti, G. Al- lodi, A. P. Reyes, P. M. T. P. M. Woodward, C. Fran- chini, S. Sanna, and V. F. Mitrovi´ c, Effects of charge doping on mott insulator with strong spin-orbit coupling, Ba2Na1−xCaxOsO6, Phy. Rev. Mater.7, 084409 (2023)

  14. [14]

    Hirai, H

    D. Hirai, H. Sagayama, S. Gao, H. Ohsumi, G. Chen, T. hisa Arima, , and Z. Hiroi, Detection of multipo- lar orders in the spin-orbit-coupled 5dMott insulator Ba2MgReO6, Phys. Rev. Res.2, 022063(R) (2020)

  15. [15]

    Okamoto, G

    J. Okamoto, G. Shibata, Y. S. Ponosov, H. Hayashi, K. Yamaura, H. Y. Huang, A. Singh, C. T. Chen, A. Tanaka, S. V. Streltsov, D. J. Huang, and A. Fujimori, Spin-orbit-entangled electronic structure of Ba 2CaOsO6 studied by OK-edge resonant inelastic x-ray scattering, npj Quantum Mater.10, 44 (2025)

  16. [16]

    F. I. Frontini, C. J. S. Heath, B. Yuan, C. M. Thomp- son, J. Greedan, A. J. Hauser, F. Y. Yang, M. P. M. Dean, M. H. Upton, D. M. Casa, , and Y.-J. Kim, Res- onant inelastic X-ray scattering investigation of Hund’s and spin-orbit coupling in 5d2 double perovskites, arXiv: 2504.20905 (2025)

  17. [17]

    D. D. Maharaj, G. Sala, M. B. Stone, E. Kermarrec, C. Ritter, F. Fauth, C. A. Marjerrison, J. E. Greedan, A. Paramekanti, and B. D. Gaulin, Octupolar versus N´ eel order in cubic 5d 2 double perovskites, Phys. Rev. Lett. 124, 087206 (2020)

  18. [18]

    Voleti, D

    S. Voleti, D. D. Maharaj, B. D. Gaulin, G. Luke, and A. Paramekanti, Multipolar magnetism ind-orbital sys- tems: Crystal field levels, octupolar order, and orbital loop currents, Phys. Rev. B101, 155118 (2020)

  19. [19]

    Voleti, K

    S. Voleti, K. Pradhan, S. Bhattacharjee, T. Saha- Dasgupta, and A. Paramekanti, Probing octupolar hid- den order via janus impurities, npj Quantum Mater.8, 42 (2023)

  20. [20]

    Morrow, J

    R. Morrow, J. Yan, M. A. McGuire, J. W. Freeland, D. Haskel, and P. M. Woodward, Effects of chemical pres- sure on the magnetic ground states of the osmate double perovskites SrCaCoOsO6 and Ca2CoOsO6, Phys. Rev. B 92, 094435 (2015)

  21. [21]

    L. S. I. Veiga, G. Fabbris, M. van Veenendaal, N. M. Souza-Neto, H. L. Feng, K. Yamaura, and D. Haskel, Fragility of ferromagnetic double exchange interactions and pressure tuning of magnetism in 3d−5ddouble per- ovskite Sr2FeOsO6, Phys. Rev. B91, 235135 (2015)

  22. [22]

    Kanamori, Theory of the magnetic properties of fer- rous and cobaltous oxides I, Prog

    J. Kanamori, Theory of the magnetic properties of fer- rous and cobaltous oxides I, Prog. Theor. Phys.17, 177 (1957)

  23. [23]

    St¨ ohr and H

    J. St¨ ohr and H. K¨ onig, Determination of spin- and orbital-moment anisotropies in transition metals by angle-dependent x-ray magnetic circular dichroism, Phys. Rev. Lett.75, 3748 (1995)

  24. [24]

    H. A. D¨ urr and G. van der Laan, Magnetic circular x-ray dichroism in transverse geometry: Importance of non- collinear ground state moments, Phys. Rev. B54, R760 (1996)

  25. [25]

    Shibata, M

    G. Shibata, M. Kitamura, M. Minohara, K. Yoshi- matsu, T. Kadono, K. Ishigami, T. Harano, Y. Taka- hashi, S. Sakamoto, Y. Nonaka, K. Ikeda, Z. Chi, M. Fu- ruse, S. Fuchino, M. Okano, J. ichi Fujihira, A. Uchida, K. Watanabe, H. Fujihira, S. Fujihira, A. Tanaka, H. Ku- migashira, T. Koide, and A. Fujimori, Anisotropic spin- density distribution and magneti...

  26. [26]

    Sibille, N

    R. Sibille, N. Gauthier, E. Lhotel, V. Por´ ee, V. Pom- jakushin, R. A. Ewings, T. G. Perring, J. Ollivier, A. Wildes, C. Ritter, T. C. Hansen, D. A. Keen, G. J. Nilsen, L. Keller, S. Petit, and T. Fennell, A quantum liquid of magnetic octupoles on the pyrochlore lattice, Nat. Phys.16, 546 (2020)

  27. [27]

    Bhardwaj, S

    A. Bhardwaj, S. Zhang, H. Yan, R. Moessner, A. H. Nevidomskyy, and H. J. Changlani, Sleuthing out ex- otic quantum spin liquidity in the pyrochlore magnet Ce2Zr2O7, npj Quantum Mater.7, 51 (2022)

  28. [28]

    Suzuki, N

    M. Suzuki, N. Kawamura, M. Mizumaki, Y. Ter- ada, T. Uruga, A. Fujiwara, H. Yamazaki, H. Yu- moto, T. Koyama, Y. Senba, T. Takeuchi, H. Ohashi, N. Nariyama, K. Takeshita, H. Kimura, T. Matsushita, Y. Furukawa, T. Ohata, Y. Kondo, J. Ariake, J. Richter, P. Fons, O. Sekizawa, N. Ishiguro, M. Tada, S. Goto, M. Yamamoto, M. Takata, and T. Ishikawa, A hard X- ...

  29. [29]

    J. E. Arnold, A. S. Johnston, and S. M. Pinsky, The influence of true counting rate and the photopeak fraction of detected events on anger camera deadtime, J. Nucl. Med.15, 412 (1974)

  30. [30]

    Suzuki, H

    M. Suzuki, H. Muraoka, Y. Inaba, H. Miyagawa, N. Kawamura, T. Shimatsu, H. Maruyama, N. Ishimatsu, Y. Isohama, and Y. Sonobe, Depth profile of spin and orbital magnetic moments in a subnanometer Pt film on Co, Phys. Rev. B72, 054430 (2005)

  31. [31]

    B. T. Thole, P. Carra, F. Sette, and G. van der Laan, X-ray circular dichroism as a probe of orbital magnetiza- tion, Phys. Rev. Lett.68, 1943 (1992)

  32. [32]

    Carra, B

    P. Carra, B. T. Thole, M. Altarelli, and X. Wang, X-ray circular dichroism and local magnetic fields, Phys. Rev. Lett.70, 694 (1993)

  33. [33]

    Tanaka and T

    A. Tanaka and T. Jo, Resonant 3d, 3pand 3sphotoemis- sion in transition metal oxides predicted at 2pthreshold, J. Phys. Soc. Jpn.63, 2788 (1994)

  34. [34]

    J. B. Mann,Atomic Structure Calculations. I. Hartree- Fock Energy Results for the Elements Hydrogen to Lawrencium, Tech. Rep. (Los Alamos National Lab., Los Alamos, New Mexico, 1967)

  35. [35]

    Herman and S

    F. Herman and S. Skillman, Atomic structure calcula- tions, inAtomic Structure Calculations(Prentice-Hall Inc., Englewood Cliffs, New Jersey, 1963) Chap. 2, pp. 1–17

  36. [36]

    Georges, L

    A. Georges, L. de’ Medici, and J. Mravlje, Strong correla- tions from Hund’s coupling, Annu. Rev. Condens. Matter Phys.4, 137 (2013)

  37. [37]

    M. O. Krause and J. H. Oliver, Natural widths of atomic KandLlevels,KαX-ray lines and severalKLLAuger lines, J. Phys. Chem. Ref. Data8, 329 (1979)